I installed a Progressive Industries Model EMS-HW50C, Progressive Industries 50 Amp Hard Wired EMS with Remote Display.
Protected the RV from low voltage - less than 104 volts many times at a campground that we stayed at over the 4th of July.
Went on a 3 week trip out west and it was nice to be able to monitor RV park voltages and current draw of appliances. Once place I was limited to 30 amps so I could monitor the loading closely.
I mounted mine in the storage compartment behind the breaker panel so wiring it up wasn't too hard. Working with 6 gauge stranded wire is a pain though.