Master Mechanic, Bi-Metal Hole Saw, 2-1/4" Arbor, M3 High Speed Steel Cutting Edge, 1-1/2" Depth Of Cut Provides Easy Cutting In The Toughest Applications, Features 3/16" Backing Plate Which Eliminates Need For Separate Drive Plate On Hole Saws Under 3" In Diameter & Prevents Mandrel Strip Out. Designed To Cut Hard & Soft Wood, Nail Embedded Wood, Stainless Steel, Pipe, Rubber & Conduit, Can Be Used With 3/8" Bi-Metal Saw Mandrel, Model #E0100687, True Value #896313, 3/8" Quick Change Mandrel, Model #E0100688, True Value #102486, 7/16" Quick Change Mandrel, Model #E0100689, True Value #752980 & 1/4" Bi-Metal Pilot Drill, Model #E0100659, True Value #779942, Bulk, Mandrel Not Included.