This product is a 5.2 BT case matching function; Support 5w*2 speakers; Support 3.5aux; Hands free call; 3pout output The voltage is 5v/ the current is 2A. After secondary development of peripheral hardware, the maximum power can be configured to reach 5W. The Bluetooth device name is ymx-878bt Power supply: DC DC voltage (3.7-5v) and current above 2a-3a; USB socket is a charging input socket; When charging, the red light is on, and when fully , the red light is not on), please select lithium battery with protection board If the function is used, two BT modules must be used (touch the key signal pin with a light switch or a wire to touch the GND ground, that is, the is connected by mutual scanning; note that it is , not a long short circuit); A module can only have ordinary BT function. When a board connected to is mono; The board is stereo when is disconnected Colour:As shown Material:PC+Metal Package Contents: 1 Amplifier Board 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.