The Sport OTE 10 wireless Bluetooth headset 4.2 stereo sports earphones with deep bass and built-in mic are compatible with all smartphones. Ergonomic ear hooks keep the headphones securely in position while you exercise. Wireless version: v4.2 Smart Voice report Range: 20 m Built-in polymer lithium battery Play time: 3 hrs Talk time: 4 hrs Working voltage: 3.6v – 4.2v Note: Please keep your headphone charged when in the low battery to achieve better Bluetooth connection and protect your battery What's in the box 1 x wireless in-ear headset 1 x USB - Micro-usb charger cable