Description SPECIFICATIONS: Drivers: 57mm speaker X 2 Transducer type: dynamic Bluetooth version: V4.1 Frequency range: 2.4GHz-2.48GHz Operating distance: up to 10m (free space) Bluetooth profiles: A2DP AVRCP HSP HFP Impedance: 16? Frequency response: 20Hz-20kHz Sensitivity: 110dB Distortion:<0.1%(THD) Music playtime: up to 40 hours Talk time: up to 45 hours MP3 play time: up to 0 hours FM play time: up to 0 hours Standby time: up to 1625 hours Charging time: about 2 hours Operational temperature: -10 to 50?C