ANTI SPLINTER DEPTH STOP: This plastic piece fit into your hole saw, preventing it from blowing through a door. It makes cleaner holes for a more professionally-installed appearance STREAMLINED PLUG REMOVAL: An access slot on the side of the saw bits allows you easy access to plugs with your hand tools. This shave off tons of preparation time for your next cut Works well with wood doors only, Manufacturer: Ounfhtrttk