The Diablo 17-Piece Hole Saw Kit features five (11) bi-metal hole saw cups, 2 SnapLock PLUS mandrels, 2 pilot bits and 2 adaptor nuts (1/2" and 5/8") for quick and easy hole saw cup changes for maximum job performance. This new, high performance hole saw set delivers faster cutting performance and increased productivity versus standard bi-metal hole saws. Unlike anything on the market, Diablo's hole saws and SnapLock Plus mandrel system simplify the attachment process for fast and efficient hole saw mounting.