Bluetooth version: 5.1 Protocol: HFP 1.7 / HSP1.2 / A2DP 1 / AVRCP 1.6/ SPP1.2 / PBAP1.0 Noise reduction version: CVC8.0 Frequency range: 2.402GHZ ~ 2.480GHZ Working distance: 10m Charging input voltage and current: 5V above 600mA Headphone battery capacity: 50mAh Charging compartment battery capacity: 2200mAh Headphone charging time 2 hours Music playing time: 4-6hours Talk time: 4-6hours