Bluetooth specification: version 1.2 compliant Bluetooth profile supported: headseet and handsfree ptofiles Frepuency range:2.4 GHZ spectrum working distance range:40 meters (class 2) dimensions (main unit):108(L)*57(W)*31(T) mm weight(main unit):129g LCD display: 96*26 dot matrix,12 digits caller number display, 15 bars volume display, battery sta-tus icon,bluet backlight DSP: full duplex transmission,noise supprew-sion and echo cancellation Pairing: up to 4 mobile phones Charging time:within 3 hours Talking time:up to 10 hours Standby time: up to 200 hours Rechargeable battery: lithium lon,3.6V,1100MAH installed Battery protection: over charge and over discharge protectio Input current: 305MA Input voltage: DC 5V Speaker power: 2 W Speaker impedance: 5 Ohm Sensitivity of micropone: -47 dB