Description: Support music, call, photo, voice tone, voice prompt, Chinese-English dual voice, one with two, pairing timeout shutdown (shutdown after 5 minutes of pairing state), low voltage reminder (when the voltage is less than 3.2v, it is reminded every 5 seconds, and 3.1v is turned off). This is the main function of this bluetooth receiver. Furthermore, in any noisy environment to achieve high definition calls, very beautiful sound quality to give you different enjoyment. Features: 1. Noise reduction, support any key to answer. 2. Connect with smart phone effectively, automatically match the connection program, and keep the connection state when charging. 3. Intelligent control chip to identify the sound frequency, to filter out the external noises within the range of non-human frequencies. 4. Stereo vocal cord + battery protection to meet your HD high frequency dreams. 5. The clip design keeps the ear away from radiation. 6. Delicate and compact, comfortable to wear and easy to carry. Specifications: Condition: 100% Brand New Transmission Range: 10 m Bluetooth Protocol: 4.1 Protocol Support: HFP1.6 / A2DP / AVRCP Battery Capacity: 135mAh Call Time: About 10 hours Standby Time: About 250 hours Frequency: 2.4ghz Sound Track: Stereo Usage: Clip-on Single or not: Double Stereo Color: Red Size: Approx. 58 * 15 * 14 mm / 2.2 * 0.5 * 0.5 in Weight: Approx. 23 g System State: Power off: MFB long press for 3 seconds Volume up: short press VOL+ Volume reduction: press VOL- Switching languages: double-click and hold MFB in the pairing state (red and blue lights flashing) Music control: Play pause: press MFB Last song: VOL- long press 2 seconds Next song: VOL+ long press 2 seconds Telephone Control: Answer the phone: press MFB when calling Reject the call: the duration of the call is MFB Last redial: double-click the MFB key, then press MFB to cancel the dialing LED Light Display: Power-on pairing: red and blue lights flashing alternately Connection status: blue light flashes slowly (5 seconds 1 time) Low voltage: red light flashing (0.5 seconds 1 time) Package Included: 1 x Bluetooth Receiver 1 x USB Cable 1 x User Manual 1 x Adapter Notes: 1.Please allow 1-3 cm error due to manual measurement. Thanks for your understanding. 2.Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard. 1、Noise reduction, support any key to answer. 2、Connect with smart phone effectively, automatically match the connection program, and keep the connection state when charging. 3、Intelligent control chip to identify the sound frequency, to filter out the external noises within the range of non-human frequencies. 4、Stereo vocal cord + battery protection to meet your HD high frequency dreams. 5、The clip design keeps the ear away from radiation.