This has worked perfectly for us. It does exactly what it's supposed to do, with zero issues. Almost brand new (we used occasionally for just 3 months). Selling because we've sold our travel trailer RV. Since you're looking for this you probably know what it does, but here's a good description: This model accommodates up to 50 amp electric service for your RV. (Can also easily be reduced to 30, 20 & 15 amp with your adapters.) Identifies faulty park power plus offers 4200 Joules of surge protection Analyzes circuits to verify pedestal power Indicators light up to show power status Tests for and indicated open ground, open neutral and correct polarity Perfect for motorhomes, RVs, travel trailers, campers & pop-ups. Save 50% from buying brand new from Amazon