Magnetic door stop/holder

I installed one on our entrance door, too. The cup side (mounted to the door) started to rust in two days. The white, powder coated cup base and the white stalk (mounted to camper body) look good, just the cup itself is rusting. No big deal. Maybe I'll clean it and spray some clear coat on the cup. It works very well, with a sharp jerk required to pull the door free of the magnets. I hate rust, but the convenience is worth it.