• Rechargeable Lithium-Ion Battery: 180 mAh/3.7V; Bluetooth 4.1; Driver unit: ?40mm; Frequency response: 20~20KHz; Impedance: 32 Ohms; Sensitivity: 108±3dB; Distortion: =1% at 1KHz; Rated power: 10mW; Max power input: 20mW; Transmission Range: 10 meters (32 feet). • Wireless earbuds connect to your mobile device using wireless Bluetooth technology • Push button to answer phone calls. Speak hands-free into built-in microphone • Allows you to connect to your device from up to 30 feet away • Includes three different size ear tips and stabilizer for optimum fit and stability • RoHS approved