1. -up delay DC protection, anti-shock when power off; 2. 7812 is used compatible with voltage stabilization, and the power supply range allows AC12V to AC24V; 3. The pull-in time is about 2 seconds; 4. The use power is up to 200 , which can be increased to 400 when used in mono parallel connection; 5. The circuit is simple and reliable. It is very easy to make and free of debugging; The product is suitable compatible with OCL or output power amplifier circuit, not suitable compatible with BTL! Use windings to supply power to the protection circuit, so that the power loop can be closed, otherwise the speaker ground and signal ground are mixed together, which easily produce interference and . (The common use of the front-level power supply and the protection circuit can easily produce humming). Color: As Shown Material: Plastic+Metal Package Contents: 1 x UPC1237 speaker protection 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.