Specifications:This receiver supports connecting headphones, connecting mobile phones, speakers, and cars.It can be kept plugged into your car stereo at the same time charging in the USB port while in use.You can play, pause, skip music, answer phone calls, redial the last called number or control music on the receiver.Item Name: Audio ReceiverMaterial: Plastic, MetalState Parameter:4.00V, Parameter:3.40VOperating Rated Voltage:4.00V, 3.40VPaired State Current: 4.33mA-m20.56mA, 4.47mA-22.03mAStandby Current (Bluetooth Connected): 0.43mA-8.31mA, 0.41mA-8.74mAMusic Playback Current: 19.04mA-23.21mA, 22.85mA-23.74mACall Current:23.82mA-24.05mA,25.19mA-25.78mACharging Current:100.0mAShutdown Current: 1.4uA, 1.1uAFeatures: Hands-free, Bluetooth, high clarity CallSize: 5.8cm x 1.5cm x 1.2cm/2.28" x 0.59" x 0.47" (Approx.)Instructions for Use:Power on and off: MFB long press for 3 secondsVolume up: Short press VOL +Volume down: Short press VOL-Switch language: Double-click and hold MFB in pairing state (red and blue lights flashing)Music Control:Play pause: Short press MFBPrevious song: VOL-long press for 2 secondsNext song: VOL + long press for 2 secondsTelephone Control:Answer a call: Short press MFB when you callRejected call: Long press MFB when callingUnnumbered redial: Double-click the MFB button, then short press MFB to cancel the dial outThe LED Light Shows:Boot pairing: Red and blue lights flash alternatelyConnection status: Blue light flashes slowly (1 second in 5 seconds)Low voltage: Flashing red light (0.5 seconds 1 time)Notes:Due to the light and screen setting difference, the item& 39;s color may be slightly different from the pictures.Please allow slight dimension difference due to different manual measurement.Package Includes:1 x Audio Receiver1 x 3.5mm Metal Adapter1 x USB Charging Cable