Bluetooth version: 5.0 Output power: 40mW;     Battery capacity 35mAH , charging box is 300mh Bluetooth distance: 5-10 meters Charging time about 1-2hours Talk time is about 2-3 hours (a pair of earphones use together), music time about 2-3 hours (a pair of earphones use together), Charging box can charge for the earphons about 2-3 times. Compatible system: Suitable for mobile phones with Android 5.0 or higher or iOS 9.0 or higher. Support all mobile phones, tablets and notebooks with Bluetooth function. Please note:   once you receive the order please adjust the watch to your most suitable time.