Advantage 1: The specially kit includes 4-3/8”, 6-3/8” carbide grit hole saw with extra dust bowl. It’s more helpful for drilling the ceiling tile and installing recessed light. It’s more clean. Advantage 2: The hole saw specially sharp teeth cuts more smooth,clean . It is more faster than tradition carbide grit hole saw up to 30%. It is more faster than tradition bi-metal hole saw up to 50%. Advantage 3: The specially back removes the plug easily. It’s faster than bi-metal hole saw 2 times. Application: This carbide grit installation light hole saw kit is For 4”, 6” recessed light for wood, MDF, drywall, plaster, corn hole board, hardie board, acoustical tile, fiberglass, air brick. bCutting depth: Up to 1” . Package: The Installation light kit includes: 1 of 4-3/8”, 1 of 6-3/8" carbide drill bit, 1 of 0.43” big arbor, 2 of 3.5" HSS pilot drill bits. Extra Dust Bowl. Recessed Light Installation kit 4-3/8, 6-3/8” with Dust Bowl