Diablo, 3/8", hole saw mandrel arbor, snap lock hole saw mandrel with 3/8" hex arbor, 4" pilot bit, 1/2" adapter nut & 5/8" adapter nut, hole saw system & mandrel design simplify the attachment process for fast & efficient hole saw mounting, features 2-3/8" cutting depth for deeper holes in one pass, tool-free plug ejection, perma-shield coating for reduced friction & heat, variable tooth design, 1 size fits all mandrel fits all diablo hole saws.