Fits Any 1/2" Drill Chuck 7/16" Hex Hole Saw Arbor Kit includes 1 x 12 inch Extension Bit with 7/16" Hex Female to 7/16" Male Shank. 1 x 7/16" Hex Arbor with 1/2" Thread for Hole saws from 5/8" (16mm) to 1 1/8" (29mm) 1 x 7/16" Hex Hole Saw Arbor for Hole Saws from 1 1/4" (32mm) to 7 1/4" (184mm) Comes with TCT Pilot Drill and HSS Pilot Drill For Deep Holes in Concrete Brick and Wood Hex Key Included to Lock Arbor in place. This 12 inch Extension Fits Any 7/16" - 1/2 inch Hex Shaft Hole Saw Arbor Adaptor a Hex Screw Secures and Tightens Hex Shaft of Arbor or 7/16" Drill Attachment. Use with our Carbide Grit Edge Hole saws To Drill Deep Holes in Concrete Masonry And Brick Walls. Plumbers Use Tools for Drilling Holes for Pipes to go through walls, Electricians Use for Drilling Holes through walls for electrical wires and conduit.