Mountain 74720 20 Piece Bi-Metal Hole Saw Kit 12 pieces M3 bi-metal hole saws 2 mandrels: 5/8 UNF-18 and 1/2 UNF-20 12" long extension and 1 adapter 5/8 UNF-18 2 pilot drill piece 82mm OAL and 2 pieces 102mm OAL Packaged in a metal case