1. The depthadjustable countersink tool is made of speed steel with an 82degree rake angle, which cuts and removes chips faster, ensuring quick and smooth operation. Even after multiple uses, the countersink functions effortlessly, creating clean and consistent tapered holes for screws. The black oxide coating enhances corrosion resistance for protection. The universal 1/4inch hex shank fits standard chucks. 2. The tapered drill bit with a wide flute can quickly drill clean holes and ensure a tight fit with screws. The tapered drill can be replaced with a spare drill of the same type and size (sold separately) to extend its lifespan. 3. This set of size drills features speed steel quality that meets required specifications. HSS grade 6542 is heavier than 4241 HSS and 4341 HSS used in other similar countersink drills. 4. One of the most adjustable countersink drills for woodworking; the drill secured with a pin will never detach from the shank. quality material components ensure durability: speed steel with toughness, wear resistance, and cuttingedge retention.