The item is a DIY kit that includes all the components of the picture,you need to solder it all by yourself
The speaker protection circuit board with time delay and DC power protection
It adopts UPC1237 chip,the circuit is simple,safe and reliable.
It adopts high quality 5A relay, suitable for most amplifier board, and can be installed directly in the chassis to save space.
Operating voltage AC 12-16V, suggest to use an independent power supply for it.
Dimension : Long 69mmx wide 36mmx 25mm high the distance between two speaker Horns is 25mm

Using Debug:

Please recheck all the connection when the components were welded fine and then do the debug test.
Power on , after the relay pick-up, provide the DC to test the Electric circuit.
Here is the guide on how to do test:
On the board input (ie, the terminal connected to the amplifier output),please give the DC input which is no less than 1.5V , the relay will be released at this time, and then remove the DC, the relay will be pick-up later. Switching the polarity of the DC and test again, the relay will repeat the above action.

Both the L and R channels should be tested.