Built in Li-battery for portable use, and has USB port for recharging Contain a wired earphone, can be for wired earphone directly, or use as Bluetooth Earphone with Bluetooth receiver Round buttons, and more fit fingers, more symmetrical design, simple and elegant Control Power, Pause, Volume, Previous, Next on Bluetooth Receiver Specification: Bluetooth Version: 4.0 Version+ EDR Operation Distance: 10M Weight: 10.33g Size: 50*22*15mm Charging Time :2hours Music Time: 5 hours Talking Time: 6hours Standby time: 36hours Battery capacity: 120mAh