Features 1. The charging box is fully charged to supply two earphones for more than 2-3 cycles of charging. 2. The headset is fully charged and can support up to 2.5 hours of talk or music playback time. 3. Can play any audio file of the paired Bluetooth master device 4. Built-in microphone hands-free calling 5. Waterproof, sweatproof Functional technical parameters: Earplug weight (each): 3.5g Charging box: 28 grams Channel: Stereo Frequency response: 20Hz-16kHz Signal to noise ratio: a?￥ 95dB Battery capacity: Headphones (each) 55mAh Charging box: 400mAh Charging box for 40 minutes Bluetooth version: 5.0 Line range: 10m (free space)

http://olla.gr/j1-tws-digital-display-bluetooth-v5.0-wireless-earphones-with-led-charging-box-white/