This Spyder 600939 Tarantula 27-piece hole saw set combines Tungsten Carbide Tipped (TCT) and bi-metal technologies for versatile cutting across a wide range of materials. The set includes various TCT hole saws, which feature tungsten carbide-tipped teeth on an alloy steel body for cutting hard materials such as stainless steel, cast iron, hardwoods, nail-embedded wood, fiber cement board, brick, and ceramic wall tile up to a hardness of 6. The bi-metal hole saws are constructed with high-speed steel teeth and a flexible spring steel body, suitable for general applications including wood, plastic, drywall, aluminum, and mild steel up to 6mm thick. The kit also contains both high-speed steel (HSS) and TCT pilot bits, along with Hex8 and Hex10 arbors to support the different saw sizes. Featuring Spyder's Rapid Core Eject arbor system, the set allows for efficient core removal without prying, angled cuts, and the enlargement of existing holes. The variable tooth pitch design ensures clean cuts through material thicknesses up to 1-7/8 inches.