This product functions as specified and has worked as planned in isolating via key on/key off a 400 watt power inverter. It is well made and appears durable. I would recommend this as a good isolator/relay solution.
I have only two complaints with this product: 1) There are no instructions, basically pretty strait forward IF you understand some basic principles but could confuse a novice as to what wire to what post. and 2) There was no cover for the large 12v battery posts. This could cause a great hazard if something was to contact them and ground. A plastic or rubber cover would have been nice (I made my own).
Overall a good buy.