With sandberg speak39n go in earset you get great sound in a stylish earset the cable features a microphone and answer button for incoming calls so you don39t have to take the phone out of your pocket headphones speaker driver diameter 10 mm speaker frequency response 20 hz to 20 khz headphone type in ear speaker impedance 23 ohms volume control yes cordedcordless corded earpiece dual earpiece audio format stereo physical form factor headset case