Special attention: 1. Bat + is connected to the positive pole dc3.7v to 5V +, GNT - is connected to the negative pole; 2. The working voltage of lithium battery is 3.7V, or the DC of regulated power supply is 4.5-5v, and the current is 600-700ma when one horn is connected; about 1.5-2a when two horns are connected. The lithium powered horn is equipped with 4 Ω 3W + 3W, the regulated power 5V horn is equipped with 4 Ω 5W + 5W. If the current is not enough, there will be some bad phenomena, such as skipping or BT instability, main board restart all the time or poor sound quality / broken sound / distortion (if there is such a problem, please check your power supply); the voltage should not be higher than 5V, otherwise the main chip, power amplifier IC and related components will be damaged, please pay attention 3. Horn wiring: white 2p seat SP - / SP + from bottom to top, l-o - / l-o + connected to horn 1; white 2p seat SP - / SP + from bottom to top, R-O - / R-O + connected to horn 2 color:As shown Material:PC+Metal Package Contents: 2 x Audio 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. USB is the charging input port; 5V in can be from here; the red light is on when charging, but the red light is not on when fully ). Please choose the lithium battery with protection board; please choose the original manufacturer for the charger, Shanzhai not only can't keep up with the current, but also can't keep constant current, which is easy to damage the battery and board. Pay attention! Power supply: (3.7-5v), current should be more than 1.5a-2a If the function is used, two BT modules must be used; when the is connected to one board, it is mono; when the is disconnected, it is stereo This product is a 5.2 BT pair box function (two modules); the voltage is 5V / current is 2a, the power supply is processed by secondary development of peripheral hardware, the maximum power can be configured to 5W, and the BT device name is ymx-868bt