If I don't know my way around angle grinders, which is the hardest part, I bought a 4 1/2" guard for a 4 1/2" angle grinder with 4 1/2 cutting teeth. wheel, and the wheel would not fit on the angle grinder without actually cutting the protective cover. My regular grinding wheel literally doesn't even fit in the nutted angle grinder (so loses the whole point). Unless I'm completely wrong, DO NOT BUY THIS.