E7S Product Paramater: ● Call duration: about 4 hours ● Bluetooth version: 5.0 ● Working distance: about 10M ● Music time: 3.5 hours ● Headphone battery capacity 450MAH ● Charging compartment battery capacity: 2200MAH ● Waterproof level: IPX5 ● Music playback time: about 4 hours ● Standby time: about 80 hours ●Without Packaging Box ●NOTE: --When using for the first time, please put the earphones into the earphone case to charge(use 5V/2A USB Cable) --When using for the first time, please pair the connection --When making calls, only one earbud works --The sound is intermittent, the reasons are: ①The distance from the connected device is more than 10M. ②The partition wall. ③Nearby interfering signal connections.