Model: GE09 Bluetooth version: V5.3 Bluetooth protocols: HFP, A2DP, HSP, AVRCP Frequency: 2.402GHz to 2.480GHz Bluetooth audio decoding: AAC, SBC Bluetooth range: 10 meters Noise reduction: ENC call noise reduction Noise reduction depth: 23dB Earphone battery: Lithium ion polymer cell 40mAh/3.7V Charging case battery: Lithium ion polymer cell 300mAh/3.7V Playing time: Play music or talk for about 4 hours Work with a charging case: Play music or talk approximately 18 hours Charging time: approximately 2.5 times (2 earphones) Standby time: approximately 120H