1. Using Bluetooth 5.1 chip, low power consumption and stable signal. 2. Lavalier design, the clip is not easy to fall when moving. 3. Mini portable, more convenient to wear and use. 4, support up and down , cut , volume adjustment. 5. Car wireless bluetooth, hands-free calling function, navigation broadcast, music, bring you a high-definition sound quality experience. Product name: Bluetooth audio receiver transmitter Bluetooth version: 5.1 Connection range: 15m Product interface: 3.5mm audio interface Frequency response range: 10HZ-20HKz Signal to noise : less than 110db Battery: built-in lithium battery, fully can be used for 4-10 hours Charging : type-c Product function: receiving/transmitting two in one Product size: 60x20mm Colour:black :ABS Package Contents: 1 x Bluetooth audio receiver transmitter 1 x charging cable 1 x 3.5mm male to male adapter 1 x Chinese and English manual Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.