GOLDSTEIN STAR Bluetooth Supports two or more mobile phones connected. Long battery life, fast charging. Support for We Chat, QQ voice calls, movie. Compatible for almost all the mobile phones and tablet PC, etc. With A2DP/AVRCP high-quality stereo audio transmission and remote control protocol. Powerful noise cancellation circuit. (Active Noise Reduction.) Wired and Bluetooth automatically switch to support audio input. Charging time is about 1 hour. (Power Indicator Charging: blue light lights, fully charged: blue light goes out.) Type: Bluetooth Wireless Earphone Sound Track: Stereo Impedance: 32 OHM Earpiece: Single Transmission Range: 10m Fit Design: In-Ear Only Compatible Brand: Universal Battery Capacity: 50mAH Earpiece Design: Earbud (In Ear) Material: High Technology PVC Bluetooth Version: Bluetooth + EDR Power Level: CLASS II Output Power: 30mW Bluetooth Distance: 10 Meters Barrier Frequency Response: 20-20000 Hz Operating Voltage Range: 3.0V-4.2V Microphone Sensitivity: -42dB Play Time: About 4 5 hours Charging Power: DC5V Power Interface [The Hole] (Computer USB port, mobile phone charger, car charger.) Compatible: for Android, Apple, Microsoft, Symbian 99% of with Bluetooth Cell Phones(iOS Cell Phone Has Power Display). Features: Compact, ultra mini design, light weight, popular and easy to carry. Rechargeable, long battery life, fast charging. High-fidelity sound quality, enjoy high quality songs. Voice broadcast when you receive a call. One button to answer call, built-in microphone.