These mandrels are a game-changer in the industrial and scientific world of hole saws and accessories. Through trial and error I found that they make the installation much smoother and more precise. The set includes a variety of mandrels that fit a broad range of saw sizes. The only downside I found was that they might not fit all saws, but the majority OF the saws worked perfectly with them. Overall, these are must-have mandrels for anyone working in cutting tools..