Blue Boar Recessed Light Carbide Grit Hole Saw 4-3/8&rdquo; dia for 4 inch lights: fast cutting in drywall, lath & plaster, Hardi board: easy plug removal uses standard 5/8 18 thread hole saw arbor adptr 1" deep - Hard tungsten carbide grit edge for a long life in abrasive materials Continuous cutting edge for smooth cutting even in wood lath and plaster Cuts through drywall, plaster, CornHole board, fiber cement Hardie board, stucco, acoustical tile, ceiling tile Attaches to standard 5/8-18 2-pin mount hole saw arbor and works with Hole Pro XL-Arbor/Shield Kit or Hole Pro X-230+ model Open back design for faster cut plug removal