1/4" Diameter Window/Door Drywall Zip Bit, Down Spiral Bit For Fast, Extra Clean, Dust Free Cuts Through Drywall, Paneling, Plywood & Foamboard Up To 1" Thick, 1/4" Size Is For Large Jobs; Doorways, Windows & Medicine Cabinet Cutouts, Use With RotoMite Or SpiraCut RotoZip Power Tools.