1. The speaker protection board has the functions of start-up delay (about 3 seconds) and DC protection (starting control voltage about 1V), the board circuit is simple, and the work is safe and reliable.2. With LED indicator, it lights up when working, and goes out when the protection starts and controls. relays are used, which is suitable for most amplifier boards3. Speaker protection requires winding supply, and cannot share with other circuits4. Small size and easy installation. And the circuit is simple and reliable. It is very easy to make and does not require debugging5. It has the characteristics of start-up delay, DC protection, -off shock resistance, simple peripheral circuits, good protection performance, and high charging accuracy.Working voltage AC: 12-18V, supply is requiredColour: BlackMaterial: PCB+metalPackage Contents:1 x Horn Protection BoardOnly the above package content, other products are not included.Note: Light 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.