First of all, yes they are plastic caps. They won't last forever. However, if you install them properly, they will sit nice and neat. Watch YouTube videos to learn more and slide the metal ring over the bottom notch for a snug fit. In fact, they were almost difficult to put on, so any doubts I had were immediately dispelled. I installed these hubcaps yesterday and they have survived a 150 mile ride. They look great and even though it's a temporary investment I'm happy.