1HSS Hole Saw: The hole saw is made of high speed steel, has high hardness, good wear and heat resistance, adopts special heating process that prolong the service life and prevent rust 2Sharply Cutting Edge: The high speed steel cutting edge provides impact resistant teeth and anti tooth stripping, the sharply teeth could provide clean, smoothly and high precise cutting 3Easy Chip Evacuation: The unique hole design of the hole saw can easily evacuate chips and improve drilling efficiency 4Flexible Spring: The spring on the heavy duty mandrel form a flexible backing that allows the hole saw to absorb the effects of the work of drilling holes in difficult to cut materials, make the cutting work easier 5Usage: This mandrel hole saw is ideal for cutting holes in soft metal, wood, PVC board, plastic and plasterboard, not recommended for hardwood, hard metal and stone