Earphones & Headphones, 70 page

Gourmandies Disney Alice Stereo Earphones Black DN-345BK

ELPA Wireless Stereo Headphones Headphones 000Hz 1m 20~20 Approx. RD-IR200

Skullcandy Official Store Riff Wireless2 Wireless Headphones 34 Hour Playback Bluetooth Deep Bass with Microphone On-Ear Multi-point 5.2 S5PRW-P740

AMVR Earphones Headphones Wired for Quest 3 Headphones Canal Type Lightweight Earphone Silicone Holder with Ear Caps In-Ear (White)

Audio Technica SOLID BASS Inner Ear Headphones Black BK ATH-CKS550

FOSTEX Dynamic RP Stereo Headphones T50RPmk4 Equipped with a Flat Diaphragm Connection Compatible Semi-open Fully-driven Driver/balanced

Bluetooth Wireless ANC Active Noise 60 Hours Only Lightweight Closed HIFI Sound Sound Leak Language Birthday Bluetooth Stereo Japanese Instruction

Sanwa Supply Tablet Headset Mini Plug Binaural Type Silver 3.5mm (4 Pole) MM-HS525TABN

Antlion Audio Kimura Solo Headset IEM Headset In-Ear GDL-1100

ELPA Light Over Headphones Headphones Wired 000Hz 20~20 Approx. 1.2m RD-NA12

Austrian Headphones Audio/Hi-X15 Over-ear

Headphones Bluetooth Headphones Wireless Gaming Headset Sealed 158g Lightweight Headphones Wired and Wireless Charging HiFi Sound Quality Stereo Sound

Panasonic Stereo Headphones Black RP-HT260-K

Elecom Headset Microphone PS4 Compatible USB Single Ear Overhead 1.8m HS-HP21UBK

Lightning Connection Headphone Microphone EHP-LF12CMBU (Blue)

Headset Bluetooth Wireless Headset Bluetooth Headphones with Microphone Compatible with Binaural aptX HD Dual Microphone CVC Noise Canceling Class 1

AKG K72 Headphones Closed-Back

Dragon Ball Z Final TWS Completely Wireless Earphones × (Vegeta)

Kiyoraka Cordless Headphones "Rakuraku Kiku-chan" HP-001

Bluetooth Wireless MUSIC LBT-F10IWH (White) Headphones/FAST

Headset Bluetooth Single Ultra Long Talking HD Strong Noise Microphone Designed for Noise Cancellation and Voice Control V5.0 Ear, Earphones, Calling,

HyperX Cloud Stinger Core Gaming Headset with Inline Audio Control 2 Year Warranty Home Work Telework Video Conference Remote Work

Elecom Headset Low Latency Flexible Arm Detachable Microphone Arm Mute Function Volume Adjustment Adapter Included Overhead Type Binaural Black

Vertex Standard Stereo Headphones YH-77STA

Docooler IR Infrared Wireless Headphones Stereo Headset Wired Earphones Dual Channel for Car DVD Player

KENWOOD JVC Kenwood JVC Sealed Headphones Foldable White HA-S400-W

Stereo Inner Ear Headphones Reel Type PG-SIH4PK4 (Pink) 0.8m

Premium Style Bluetooth Installed PG-BTE12IE2WH (white) 5.0

Owltech Wired Single Ear Earphone Can Be Worn On Either Left or Right Comes with Clip Cable Length Black Microphone, Ear, Microphone, 1.0m,

Elecom Headset Microphone Single Ear Overhead 1.8m HS-HP21SV

Earpiece with Ear Hook for Canal Type Earphones Compatible with Round Canal Type Earphones with Inner Diameter of For Earphones Fall Prevention Fall

Premium Style Wireless Stereo Earphones with Bluetooth Tough Ear Type Black 5.0 Cable/Inner PG-BTE12TC1BK

Digital Wireless Headphone System Black Audio-Technica ATH-DWL550

CROWD AUDIO Noise Canceling Headphones Wireless Headphones Can Also Be Used with Wired Gaming Headphones Online Meetings Remote Meetings Telework

SITOAT Bluetooth Wireless Active Noise Large Ear 50 Hours Low Closed HIFI Deep Sound Leak Language Birthday Bluetooth Japanese Instruction Black

Ohm Denki AudioComm Wireless Bluetooth Stereo Bluetooth Smartphone Smartphone White OHM Headphones, Headphones, 5.3, Calls, Calls, Hands-Free Calls,

Victor Foldable Flat Headphones Closed Type Red HAS160R Product

Hitachi Maxell Canal Headphones Light Blue (Reel Type) MXH-C110RLB

SEIWA Car Supplies Bluetooth Mono Earphones BTE110 Waterproof Single Ear Hands-free

Elecom Headset Wired Neckband with Microphone 4 Pole Connection with Telework PS5 PS4 Nintendo Mute Function Lightweight Flexible Arm Binaural Black

Meisei Bluetooth Gaming Wireless Bluetooth MicroSD Card MP3 Wired and Sealed HiFi Sound Folding Compatible with Headphones, Headset, 5.3 Earphones,

Wireless Cat Ear Headphones Pink Bluetooth Wireless with LED Cute Sparkling Rainbow Color Instruction Manual and Easy To Size Adjustable Christmas

Buffalo PC Headset with USB Connection and Noise Canceling Black BSHSHUS315BK Microphone,

Sanwa Supply Multimedia Headphones Stereo Mini Plug 3.5mm MM-HP208N

TAK4607 Bone Conduction Bluetooth Wireless Earphones Size Adjustable Headband with Adjustable Adjuster Waterproof Standard IPX5 [Philips] (Green)

Elecom Headset Microphone 4 Pole Binaural Neckband Durable Cord 1.8m HS-NB05TSV

Wireless Headphones Headset Wireless Headphones Bluetooth Headphones Wired and Wireless Dual Use Headphones Headphones Equipped with Volume Control

For Electronic BOREHO WH White Lightweight Sound Insulation Sealed Type Mini Standard Plug [Headphones Piano/keyboard] BH-181 (Stereo 3.5mm

Elecom Gaming Single Ear 1m with Extension Smartphone Compatible with PS4 Black Headset, Overhead, 1.5m Cable, Game, Switch, HS-GM10BK

Elecom Headset Wired Neckband with Microphone 3 Pole Connection Function Volume Adjustment Flexible Lightweight Binaural Black 3.5mm [Mute Arm] 1.8m

Jabra Perfom45

CROWD AUDIO Dual Cable Headphones Wired Heavy Bass Cable Detachable Headphones Jack Intercom Simultaneous Connection HP-04 6.5mm 3.5mm

SITOAT Bluetooth Wireless ANC Active Noise 60 Hours Only Lightweight Closed HIFI Deep Sound Leak Dual Language Birthday Bluetooth Japanese Instruction

Maxar Electric Earphones That Can Be Used with High Grade Cord Length 1m Plug Monaural Soft Ear Inserts That Are Gentle On the Ears [Special Plug]

Decostatue Miku Nakano Japanese Original Voice Cosplay Bluetooth Card Convertible To Wired Anime Japanese Instruction Manual Earphones, Pack,

Audio Technica Inner Ear Headphones Navy NV ATH-LS50

Buffalo BUFFALO Binaural Neckband Headset Black BSHSN02BK

Sanwa Supply Bluetooth Bone Conduction Headset MM-BTSH69BK

Kashimura Earphone Compatible with Both Calls and Incoming Exclusive for External Connection with Switch and with Rotating Clip Microphone, Calls,

Headphones Bluetooth Wireless Headphones Bluetooth Headphones Wired Wireless Dual Use HIFI High Sound Quality Up To 38 Hours Continuous Playback

Earphone Microphone Product Kashimura/Bluetooth Number BL-66

Audio Technica CZ Headphones Wired Ear Hook Ear Fit Crazy ATH-EQ500

SteelSeries Gaming Headset Compatible with Arctis Prime PC PS5 PS4 Switch Wired Microphone Supervised by Pro Gamers High Resolution Sealed Playback

Set of 3 Compatible with Kenwood Intercom Earphone Microphone for Demitos 1 Pin Digital Simple Wireless Compatible Compatible FIELD GEAR FGKTPZ3

Elecom Wireless Single Earplug with Microphone Power Volume Button Support That Can Listen To 2 Communication Devices At the Same White Headset,

Razer Kraken

Elecom Headset Overhead with Microphone USB Mute Function Volume Adjustment Flexible Arm Lightweight Small Single Ear Black Width 133mm X Depth 50mm X

Set of 3 Kenwood Compatible Intercom Earphone Microphone for Demitos 2 Pin Compatible VOX Compatible FIELD GEAR FG3 UBZ-LP20 UBZ-LM20 UBZ-LK20

Elecom Headset for Low Volume Foldable 4 with Rotating Microphone Both Navy X Yellow Children, Specification, [3.5mm Connection, Poles] Arm, Ears,

Elecom Headset Smartphone Microphone 4 Pole One Ear Overhead Durable Cord 1.8m HS-HP21TBK

Asus ROG Cetra II Core Gaming Headphones Liquid Silicone Rubber by Inline Microphone Mm Volume Control 18g PS5 PS4 Switch PC Smartphone Earphones

ELPA Sealed Headphones Headphones Wired 000Hz 20~20 Approx. 3.0m RD-OH50

Elecom Headset Microphone 4 Pole Binaural Overhead 1.8m HS-HP22TBK

DIAMOND ANTENNA Daiichi Denpa Kogyo Diamond Handy Earphone Soft Type Icom Yaesu HE37 (for Marantz)

Tama Electronics Industry inG Mono for Smartphones Black TSH36SMK Hands-free

Elecom Bluetooth Headset Extra Small HSC31PC with USB Charging Cradle Black LBT-HSC31PCBK

NICEHCK EBX25Ti Earphones 1DD Wired Dome Beryllium Plated Diaphragm Dynamic Driver Titanium Alloy Cavity MMCX Interchangeable Design 6N Single Crystal

Poly Wired Headset Blackwire 3210 Noise Canceling with Microphone Lightweight Year Manufacturer Windows Mac Chrome Web Conference Earphones Microphone

FIIO JT1 from Authorized Japanese Number Headphones Headphones FIO-JT1-B [Ships retailer/Serial Included]

SIMOLIO Headphones Bluetooth with Microphone and Shared Volume Limit Hearing Suitable for Children and Wired Wireless Suitable for Game Gray 712G

AIAIAI DJ XE DJ Monitor Headphones TMA-2

Elecom Headset Bluetooth Waterproof One Ear Calling White Approximately 25 X 54 X 35 Mm (IPX5 Compatible) Hands-free LBT-HSC10WPMPWH (excluding

ELPA TV Stereo Headphones Wired Canal Earphones 000Hz 20~20 Approx. 3.0m RD-HV03

HIFIMAN Planar Magnetic Field Driven Headphones Edition XS

Alinco EME-58

Edifier WH700NB Pro Wireless Headphones with ANC Bluetooth Equipped with Noise To 56 Hours Sound Noise Latency Game Mode Headphones with Microphone PC

Elecom Headset Microphone USB Binaural Overhead Single Cable 1.8m HS-HP28UBK

YAMAHA YAMAHA Studio Monitor Headphones HPH-MT5W

Stereo Inner Ear Headphones Reel Type PG-SIH3PK4 (Coral Pink)

Parts Express Mini Stereo Lightweight Headphones with Cord 4'

Electronic Piano Headphones Shimamura Musical Instruments Original Audio-technica ATH-EP700S2 (White) Audio-Technica

Headphones Wired for TV with Volume Controller Black Audio-Technica ATH-350TV

Elecom Headset for Children Foldable Connection 4 Black X Red [3.5mm Poles] HS-KD02TBKR

Elecom Headset USB Connection Dual Microphone Noise Reduction with Mute Volume Function Earphones Binaural Black HS-EP101UNCBK

Stereo Headphones Lighting Driver Ma EHP-LF10IMARD (Red) 13.6mm

Buffalo BUFFALO Single Ear Headband Headset 4 Poles BSHSHCM105BK

Elecom Headset Bluetooth Wireless Charging Stand Included Up To 19 Hours Talk Wireless Microphone Headphones Unidirectional Button Operation Connect 2

Sanwa Supply Waterproof Bluetooth One Ear Headset FREE MM-BTMH41WBKN

iClever Bluetooth with Wireless and Wired Dual LED Wired 25h Volume Limit Audio Stereo Foldable Suitable for Children and Suitable for Game Blue Green

Audio Technica Headphones Wired Sealed Aluminum Housing Compatible with High Resolution Sound Source Cable 3m ATH-A900Z

Kashimura Bluetooth Earphone Microphone with Double Microphone That Clearly Communicates To the Other Party NBL-119

Open Monitor Headphones Wired Mix Mastering Music Listening Detachable Cable with Conversion Adapter Open Back Studio Monitor Audio-Technica ATH-R70xa

Bluetooth Wireless Sealed Deep Bass Headphones with Lightweight TF Birthday Bluetooth Storage Bag Included Headphones, Headphones, Over-Ear

With Bluetooth HIFI High Sound NAZUSA Wireless Bluetooth Dual HIFI High Sound Up To 38 Hours of Continuous Sound Leak Noise Fast Charging TELEC

Sanwa Supply Ultralight Bluetooth Open Ear Headset MM-BTSH71BK

Razer Moray Gaming Earphones Hybrid Dual Driver Monitors Thin Shape Passive Noise Isolation Braided Cable Detachable OFC MMCX Wire Custom Eartips

JVC Kenwood JVC Sealed Headphones for Kids Pink HA-KS2-P

Razer Kaira

Elecom Headset Wired Ear Hook USB Connection Microphone Single Ear Remote Work Black HS-EH01UBK

Poly Wired Headset Blackwire 3220 Noise Canceling with Microphone Lightweight Year Manufacturer Windows Mac Chrome Web Conference Earphones Microphone

SIMOLIO Kids Equipped with Call 94db Volume Hearing Learning Green 902N Children's Headphones, Headset, Microphone, Limit, Protection, Foldable,

JVC Open Headphones Lapis Blue HP-AL102-A On-Ear Ear-hook

SEIWA Car Supplies Bluetooth Monaural Earphone Cradle BTE102 In-Car Hands-Free

Yaesu Wireless Bluetooth Earphone Microphone SRS220A SRS220SA SR235 SRFD1 SRFD1M SR820 SR740 SR741 SRM420 SRM320 Compatible Successor Product STM-320R

Kashimura Earphone Microphone Compatible with Both Calls and Incoming Compatible with Stereo Mini with Switch and Volume Calls, 3.5mm Jack,

Elecom Headset Wired Ear Hook USB Connection Microphone Binaural Remote Work Black HS-EH02UBK

Elecom Headphones for Children Connection 4 With Rotating Microphone Arm Black Width 121 X Depth 43 X Height 122 Mm Not [3.5mm Poles] HS-KD01TBK

Elecom Headset Wired Connection 4 Pole for Children with Rotating Microphone Arm Lightweight Stereo Black 3.5mm HS-KD03TBK

Ear Cuff Earphones Trend In OWS Air Conduction Bluetooth Wireless Innovation In Bone Conduction Open Sound Leakage Earphones That Do Not Block the

Tama Electronics Industry Mofusand Completely Wireless Phone 2 Waterproof Level IPX4 Blue Shark (Baby Nyan) SQ-BS75BB-MS1

Headphones Megadream Headphones with Cat Ear LED Sides RGB Light Bluetooth Length 1m TF Card Size Children's Wireless/Wired Microphone, Light/Both

Elecom Headphones for TV Driver Black [Overhead Type] 30mm "Affinity Sound" 5.0m EHP-TV11O5BK

Sanwa Supply Bluetooth Headset Dual Microphone Noise (with Cancellation) MM-BTMH68BK

JVC Kenwood JVC Sealed Stereo Headphones for Indoor Use TV and Extension Cord Included HA-RZ910 (for Games) 1.2m + 2.3m

Elecom Headset Wired Neckband Foldable USB Connection Microphone Binaural Remote Work Black HS-NB06UBK

JVC KENWOOD Wireless Headphones Bluetooth with Microphone Telework 35 Hours Continuous Playback White KH-KZ30 Multi-point KH-KZ30-W

Audio Technica Open Monitor Headphones Wired Mix Mastering Music Listening Detachable Cable Conversion Adapter Included Open Back Studio Monitor

Elecom Headset Overhead with Microphone 4 Pole Connection with Telework PS5 PS4 Mute Function Lightweight Flexible Arm Binaural Compact Black 3.5mm

PChero Headset for Landline One Ear Telephone Noise Canceling Microphone Mute RJ9 Wired Headphones for Call Center Compatible with Hitachi Oki Avaya

Elecom Headset Mini Plug Overhead Wired Single Ear Conversion Cable 30mm Driver Black 4-Pole HS-HP29TBK

Roland Monitor Headphones Wired Black RH-5

Elecom Bluetooth One Up To 18 Hours of Lightweight and Less USB Black Headset, 5.2, Wireless, Ear, Calling, Fatigue, Calls, Voice/Mute Control,

OneOdio ProC Wireless Headphones Bluetooth Headphones Wired Wireless Dual Use Bass Enhancement Bluetooth AAC Compatible 110 Hours Playback Microphone

Elecom Headset Wired Neckband Foldable Connection 4 Pole Conversion Cable Included Microphone Binaural Remote Work Black 3.5mm HS-NB06TBK

Kingjim Meets Headset That Does Not Block Your Ears "Call (wired Type)"

Elecom Headset with Microphone Arm USB Inner Ear Wired Single Ear Black HS-EP16UBK

DOQAUS Bluetooth Wireless Up To 80 Hours of Continuous 3EQ Sound Wired Sealed Memory Compatible with and Walkmans LIFE3 Headphones, 5.3, Headphones,

Elecom Headset Wired Overhead with Microphone USB Connection Function Volume Adjustment Flexible Lightweight Large Binaural Black [Mute Arm] 1.8m

OneOdio Pro30 Wired High Resolution Monitor DJ Studio Movies Headphones, Headphones, Headphones, Headphones, Recording/Instrument

Sennheiser Wireless Headphones ACCENTUM Wireless Black High Performance Driver 50 Hours Playtime Noise Canceling Clear Calls

Poly Voyager 5200 UC Bluetooth Wireless Single Monaural Earphone Noise Canceling Compatible with PC and 2 Year Manufacturer Headset, Ear, Type,

Suigetsu Ame Moondrop Kadenz Canal Earphones Wired Replaceable Recable Balanced Cable Single Dynamic Diamond Coated Diaphragm 2Pin Connector USB-C

Elecom Headset Wired Microphone 4 Pole Single Ear Hook 1.8m HS-EP13TBK

Sanwa Supply Bluetooth Headset Charging Ultra-compact One-ear (with Case) MM-BTMH52BK

HyperX Cloud Alpha Gaming Headset Inline Volume Control Box Included Red Original Data Bonus HX-HSCA-RD/AS (4P5L1AB#UUF)

Buffalo BUFFALO Single Ear Headband Headset USB Connection

Headphone Wired Cable Mini Connection Black Audio-Technica ATH-AVC300 3m/6.3mm Standard/3.5mm

USB Inner Ear Headset Compatible Noise Canceling Microphone Hand Control Treatment Cord Small Size Audio-Technica Type-A Type-C

Razer Kraken Green Gaming Headset Analog Connection PS4 PS5 PC Switch Smartphone Cooling Gel Pad Authorized Distributor Guaranteed [Japanese Product]

Buffalo BUFFALO Binaural Headband Headset 4 Poles

OneOdio Monitor Headphones DJ Headphones Compatible with Studio Recording/Instrument Practice/Mixing/Watching TV/Watching Movies/Games, Etc.

Elecom Headset 4 Pole Noise Canceling Unidirectional Light Wired Headphones with Microphone Long Time Web Conference Telework Black 3.5mm HS-HP06STBK

Elecom Wired Headset with USB Mute Volume Lightweight Remote Web Black Microphone, Neckband, Function, Adjustment, [Telework, Work, Conference],

Elecom Headset USB Wired Headphones with Microphone Lightweight Long Time Web Conference Telework with LINE Skype Windows Online Silver [Compatible

Panasonic Clip Headphones Red RP-HZ47-R

Elecom Headset with Microphone Arm USB Inner Ear Wired Binaural Black HS-EP15UBK

Elecom Stereo Headphones Compatible with iPhone Android Canal Fittone CS3531 Red (with Microphone) & EHP-CS3531RD

Elecom Stereo Headphones Canal GrooveGangsta Series Dynamic Driver Powerful Bass Gold 10mm EHP-CN400AGD

Elecom Stereo Headphones Canal Colors Neon 2 (with Microphone) EHP-CC100MNE2 EHP-CC100MNE2

Panasonic Stereo Inside Phone Sealed Silver RP-HJS250-S

USB Stereo Earphones White Type-C

Elecom Canal Type Headphones EAR DROPS Aqua EHP-AIN80BU

Pai Audio Type MR3 Burgundy Triple Balanced Armature Earphones Burgundy Semi-open PAI-MR3

Earphones In Earphones Bracelet Earphones Hand Strap Headphones Wired Earphones Earplugs Wire Portable Headset Personality Creative Universal Gift

FSC Single Earphone Wired Earphone Cable Canal Type Sleeping Phone Earphone While Sleeping Silicone Earpiece Remote Control Volume Adjustment

Headphones with Microphone Earplug Type Lightning White Stereo 10.0mm

Cubilux Type C Earphone 192 USB Type C Wired Headphones with Compatible with iPhone iPhone 15 Pro iPad 10 iPad Pro iPad Air Samsung Ultra Note Tab

Sonic School Headset Binaural Plug Shift Plus Violet 3.5mm LS-5156-V

Ohm Electric AudioComm Single Inner Phone Silver OHM HP-B171N-S 03-2431

Audio Technica Inner Ear Headphones Red RD ATH-LS50

Softbank GLIDiC Sound Air C&S TW-7000 SB-WS72-MRTW

Bone Conduction with Ear Open Do Not Block Your Headphones for Elderly Bicycles Earphones, Wired, Microphone, Sports, Sweatproof, Splashproof,

1MORE Fit Open Ear Earphones S50 Sports Earphones That Block Your Bluetooth Air EQ IPX7 Fast 38 Hours Includes Running Training Don't Ears, 5.3,

Panasonic Closed Headphones Silver RP-HT560

Voyager Focus UC Poly(old Model) B825-M

Radius Inner Ear Headphones Black High Resolution Compatible HP-NHR22K

Miyoshi MCO Earphones with USB A Hand Controller Weight Product Warranty 6 Months White Single-ear Microphone, In-ear Type, Retractable, Connection,

Excel Sound Inner Ear Stereo Headphones 5m EH-5S

Sanwa Supply Bluetooth Headset External Black Free (with Microphone) MM-BTMH61BK

Tubomi DH298-A1Bk

YAMAHA Yamaha Headphones B [] HPH-50

Tumuri DH303-A1

Elecom Stereo Headphones (with Microphone)/canal/10.0mm/black

Sennheiser Sennheiser Open Headphones HD599 [item]

Tune 710BT Wireless Headphone Bluetooth Sealed 770NC 760NC 750BTNC 600BTNC 520BT 500BT 510BT Compatible with Lebakort Storage Case (Off-White Case)

Superlux Sealed Headphones White HD581 White

Buffalo PC Headset USB Connection Large Driver Black BSHSHUS305BK

Gaming Headset Zero 7 Color LED Light Headset Noise Canceling with Microphone Wired Gaming Headphones Switch Headphones Lightweight Fully Effective

Tama Electronics Bluetooth Headset Stamina TBM20SBK Ver.5

Digital Terrestrial Earphones 3m Black Over-the-ear MDE-EH3

GLIDiC Sound Air Black TW-5100

Hifi Kingdom EPZ K5 8mm Moving Coil Balanced Armature Hybrid Professional HiFi Monitoring Earphones Earphone Panel Maple and 3D Medical Resin Acoustic

Wireless Cat Ear Headphones Blue Bluetooth Wireless with LED Cute Sparkling Rainbow Color Microphone Japanese Instruction Manual Included Foldable and

Newzerol New Release Wired Gaming Earphones Charging Adapter Compatible with For Quest 3S Compatible with PD100W Charging Port Enables Charging and

Fanmusic TRN BT30 Pro True Wireless Bluetooth Earphone Module Connector Replaceable Not (Headphones Included) (0.75mm)

Headphones Wired Cable Mini Connection Black Audio-Technica ATH-AVC500 3m/6.3mm Standard/3.5mm

Asus Gaming Headset ROG THETA Nintendo Mac Equipped Real Surround Sound 8 Independent Essence Drivers AI Noise Canceling Microphone Special Cooling

Maxell 190319 Lightweight Stereo Black by Maxell HP-100 Headphones, [item]

Earphones Earphones of Wired Earphones with Microphone USB C Noise Canceling Compatible with Play Pixel XL Compatible with Samsung Galaxy S20 S21 FE

Audiophile Portable Audio-technica Ath-Es500bk