For electricians, AVELE01 includes 15 bimetal and 9 carbide-tipped hole saws in range of diameters, designed for fast cuts in abrasive materials such as fiberglass, drywall, aluminum and countertops. For plumbers, 13 bimetal and 9 carbide grit hole saws with several diameters meet cutting requirements through pipe tap and entrance sizes up to 4 in. Carbide grit hole saws provide clean cuts in thin materials and cut very hard, abrasive materials such as hardened steel, cast iron, brick, cement, ceramics, computer flooring, composites and acoustic tile. Arbors and replacement pilot drills are included with each kit.