Headband headphones wireless headphones bluetooth headphones battery life 8 10hrs charging time 3 4hrs bluetooth frequency 2402 2408 bluetooth version v21 edr supported bluetooth profiles a2dp avrcp hsp hfp series maxell hb type of fitting over ear transmission mode cordless features microphone headset compatible with ios sound function in line volume control sensitivity 113 dbmw impedance 32 ohm frequency response 20 20000 hz driver 40