This product built-in digital noise reduction chip, making calls clearer and 3.5mm plug design, no need to drive. It adopts bluetooth 5.0 and EDR technology, so it has many advantages such as fast transmission, strong signal and good sound quality. Built-in antenna design, 20 meters barrier-free transmission. Audio adapter made of high quality ABS and metal material, durable and lightweight. Audio player's length is 1.3cm, width is 1.3cm and height is 6.8cm. It has two different styles: without battery version(with USB cable) USB power supply, long service life and with built-in battery version(no usb cable) Built in battery: lasts about 5 hours (can be used with car charger and USB charger) Audio transmitter is suitable compatible car, listening music, call, home, etc. Item Name: Audio Receiver Material:ABS,Metal Supply Voltage: 5V Bluetooth: 5.0+EDR Frequency: 2402-2.480Hhz Bluetooth Transmission Distance: 20M FM Transmitting Frequency: 4dBm Support Agreement: A2DP V1.3/AVRCPV1.6/HFP V1.7/HID V1.1/AVCTP V1.4/AVDTP V1.3/SPP V1.2 Size:1.3cmx6.8cmx1.3cm/0.51inx2.68inx0.51in Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 X Audio Receiver 1 X User Manual 1 X USB Cable