Review on High-Efficiency 4000W Power Electronic Regulator Controller by Robert Diaz

I bought this for a project I was working on. The craftsmanship was definitely low but it looked safe enough. I benched him, used force, and he popped out the moment I did. I cracked it and it wasn't even worth fixing. I checked some components and found that some of them are on the edge of their capabilities. The rheostat didn't really work either when I put the gauge on it. The only parts I found use for were the case and heatsink.