Features:2-IN-1 Audio Adapter: One button switches between BT transmitter and BT receiver modes. Upgrades the non-BT devices into BT-enabled ones.BT 5.0 Connection: Wireless BT 5.0 technology ensures transmitting a strong signal in high-quality and high speed.Hands-free Call: It works perfectly in the car. With a built-in microphone, it supports hands-free calling. One button to answer and end calls.NFC Connection: NFC function, close to the device for connection, no need searching. (Make sure that the NFC of your phone is on.)Dual Audio Port: Comes with 3.5mm audio cable and 2RCA cable, suitable for more audio devices. Can connect 2 speakers simultaneously.Specifications:Model number: M21BT Version: 5.0Transmission Distance: 10m or 33ft (open space)Power Supply: DC 5V (1-1.2A)Color: BlackMain Item Size: 5.9x5.9x2.2cm or 2.32x2.32x0.86inMain Item Weight: 38g or 1.34ozPackage Size: 16.0x10.5x3.3cm or 6.30x4.13x1.30inPackage Weight: 123g or 4.33ozPackage List:1 x BT Audio Adapter1 x 3.5mm Audio Cable1 x RCA Cable1 x USB Power Cable1 x User Manual (English or Chinese) Note: 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.