Name: JR-CB1 Wireless Receiver Model Version 5.3 of BT Protocols supported include HSP, HFP, A2DP, and AVRCP. AAC/SBC audio decoding Distance of transmission: greater than 12 meters Range of frequency response: 20 Hz–20 kHz Sensitivity of the microphone: -38±2dB 3.0-4.2V is the working voltage. SNR: greater than 58 dB 50mW of power 300mAh is the battery's capacity. 22 hours of music at 70% volume 16 hours of talk time at 70% volume Time needed to charge: two hours Connected standby time: 27 hours Input for charging: 5V⋓1A Product dimensions: 51.4 x 35 x 13.4 mm 30g is the net weight.