Multi-tooth TCT tip thick heavy duty carbide alloy with high hardness, rust proof, sturdy and durable; With a spring to prevent jamming on operation Category Boring Diameter 22mm/0.86", 30mm/1.18", 35mm/1.38", 45mm/1.77", 50mm/1.97", 65mm/2.56" Should be installed for use in an electric drill. Widely used for stainless steel plate within 3mm, and iron plate less than 10mm, also good for hole operation in aluminum alloy metal Perfect for installing locks, knobs in doors and cabinets or drilling larger diameter holes through desks, etc. 6 pieces high quality carbide 22-65 (mm), which can cut holes on steel, stainless steel, copper, brass, fiberglass, Formica, iron, aluminum, wood and various types of pipes in seconds Features: 1. 100% brand new and high quality. 2. Made of high quality alloy steel, the blade is extremely sharp and resistant to cutting. Good perforation. 3. Taking advantage of using our HSS hole saw set, it can be used for thick steel plate and thick-walled metal pipe