Transmitter distance: 10m/33ft.
BT protocol: HFP, A2DP, HSP, AVCRP.
Frequency range: 20-20000Hz.
Charging box capacity: 3.7V 450mAh.
Headphone battery capacity: 2*3.7V 50mAh.
Music playing time: about 4 hours (depends on the music volume).
Charging time: about 1.5 hours for the earphone, 2 hours for the charging box.
Headphone size: 25*30*26mm.
Charging box size: 62*40*27.2mm/2.44*1.57*1.07in