I removed this from my popup before I traded it in - used for two seasons. I couldn't find any place to install it in the new 179 I bought where I would be satisfied. So, I'm selling it to get the one that is outside the camper on the cord. It is the hard wire model with built-in display. And It definitely works because I discovered the 30 amp outlet in my house that the previous owner installed had the hot and neutral switched. The device would not allow the outlet to power the camper until I corrected the wiring.