Review on Jtron 400A Top Post Battery Disconnect Switch For Car, Boat, Truck, And RV - Power Master Quick Disconnect Cut Off Isolator Switch Made With Plated Copper by Seth Hogate

Good product materials. Electrically is not the best design, so you might have voltage drop.So the material, more like a brass, selection is great. The problem is that a little collar (underneath the green knob) on the top must send all the current through the bolt to the threads to the bottom plate. So the big contact area on the battery cables are greatly reduced (high current density) to screw threads which are small. This can cause contact melting and burnout and is a good reason if you have failure. Most likely when you start the car. crank down on the know for high pressure and the lowest resistance you can get.