"GENERAL TOOLS" HEX SHANK 1/4" Adjustable Pilot Set of 4 Pilot Bits ( Sizes 5 to 14 ) Drill, countersink and counterbore precision screw holes in a single operation when doing fine carpentry and woodworking Hardened high-speed pilot bits give long life Black oxide finish deters rust 1/4" hex shanks prevents slippage in electric drills and can be used in power screwdrivers Adjustable drill and high performance angle on countersink