This MrCool bi-metal hole saw and mandrel with drive pins allows you to easily cut a hole through wood, metal, plastic, or other materials. Engineered for precision cuts, this tool features both durable construction and variable teeth for decreased vibration during operation. It sports a corrosion-resistant enamel coat to protect against long term wear and tear. The sturdy backing plate is strong enough to prevent warping during routine use. Plus, the high speed steel in this saw handles heat more efficiently than previous generation high-carbon steel saws. It will slice through tougher, harder materials more easily than carbon-steel bits, and will last longer too. Sturdy, steel cutting teeth guarantee precision cuts with every use. Heavy backing plate prevents warping. Asymmetrical tooth spacing reduces operational vibration. Anti-rust, anti-corrosion enamel finish ensure years of quality performance. Approximately 5 teeth per inch.