A power cord dogbone adapter
allows you to plug into a different outlet than your RV plug will allow. So if you have a 30 amp power cord on your RV you can use this to plug into a 15/20 amp house hold outlet (garage). This would allow you to test your AC unit at home. The dogbone adapter has a length of cord on it to move the connection outside of a campground power pedestal so the lid can close. You can get these adapters without the length a cord as well.