1. Built-in large-capacity battery, high density, lock the power without loss, the use time is up to 48 hours 2. Comfortable ears, clear noise reduction 3. The surging atmosphere of the dynamic performance of the big actuator provides you with 360 degree stereo surround sound Product parameters 1. Bluetooth receiving distance: 10 meters 2. Standby time: 48 hours 3. Battery capacity: 250mAH 4. AC resistance: 160hm 5. Bluetooth chip: 5.0 6. Frequency response: 20-20000HZ 7. Available modes: support TF card, Bluetooth wireless connection

http://olla.gr/d01-bluetooth-5.0-hanging-neck-sports-wireless-in-ear-bluetooth-earphone-blue/