Imperii Electronics imperii Wireless Headphones provide real wireless stereo sound. They have individual left and right channel and HIFI sound. Both the left and right earbud are Bluetooth enabled, could be used separately, or used as one pair. They provide ultra low battery consumption with Bluetooth version: V5.0 + EDR (both sides). The Bluetooth Mode is: A2DP 1.3/HFP 1.6/HFP 1.2/AVRCP 1.6/D 11-3. The Bluetooth Frequency is 2.4 GHZ and they provide a Bluetooth Range of 15-25 m. The battery capacity is: Earbud: 30 mah rechargeable Li-on battery, Charging dock: 350 mah (optional).