Feature: Compact and light-weight design. Double-ear main and subsidiary earpiece design, innovative and excellence. Bluetooth 4.1 technology, better sound quality. Adopt True Wireless Technology Intelligent charging box provides fast charge With hight capacity lithium battery and low frequency balanced technology funtion. Multi-functional button Strong compatibility, compatible with devices as long as they are bluetooth enables. Three steps to pair, easy to use. Specifications: Type: Bluetooth Headset Color: Black Bluetooth version: V4.1 Drive: 8mm Impedance: 16ohms Power level: Class � Working voltage: 3.2V-4.2V Sensitivity: -42db±2db Frequency range: 2.4-2.48Ghz Distance: