New arbor allows for rapidmounting or removal of hole saws. Faster, easier slug removal. Drill pilot hole without saw: Eliminates the ?bite'' when saw crashes into the steel. Provides better ergonomics - reduces stress on wrist, arm and hand. Eliminates obstructed view from hole saw. Only one arbor required from 7/8 IN to 6 IN (7/16 IN shank recommended for hole saws above 2-1/2 IN). Works with recessed light and carbide grit hole saw products as well. Adapters re-usable to minimize costs. Universal - works with anybrand hole saw. Kit contains Bi-metal holesaws for 1/2 IN through 2 IN conduit sizes '