1. Bluetooth V5.3 2. Automatically connect to paired Bluetooth devices 3. Automatically shut down if no device is connected for ten minutes 4. 13 hours of music playback with full power 5. Private answering Both RX and TX support simultaneous connection to two Bluetooth devices Dimensions: 5.5x3x1.15cm Technical parameters: Charging voltage: 5V Working current: 16mA2mA Shutdown current: 15uA2uA Charging time: 50 minutes Working time: RX13H / TX16H Battery capacity: 240mAh Bluetooth version: Version 5.3 Bluetooth transmission distance: 10M in a straight line Colour:As Shown Material:plastic Package Contents: 1 x Car Bluetooth receiver and transmitter 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 picture a little different from the real thing. The measurement allowed error is +/- 1-3cm. Note: 1. Please allow 1-3 mm error due to manual measurement and 1-3g weight error make sure you don't mind before ordering. 2. Due to the lighting of the photos and the difference of monitors, the pictures may not reflect the actual color of the real item. Please make sure you don't mind before ordering, thank you! About Shipping: 1.please pay attention to your delivery address such as: name, street, house number, doorbell/email without name, etc. is correct, or the order will not be delivered correctly. 2.All items will be shipped within 3 business days after the payment is received. Most times you will receive them within 8-12 days then. The specific delivery time is depend on circumstances. 3.During the shopping process, if you have any questions, please feel free to consult us, we will reply you within 24 hours Hope you have a pleasant shopping experience!