Product Description Milwaukee 49-56-0183 3-1/4-Inch Ice Hardened Hole Saw From the Manufacturer Milwaukee Electric Tool Corporation introduces Ice Hardened hole saws, a new generation of hole saws that offer up to 50% longer life than the competition and are ideal for metal and wood cutting in a wide variety of HVAC, electrical, plumbing and maintenance/repair applications. Milwaukee Ice Hardened products utilize a proprietary cryogenic hardening process that improves upon traditional heat treat processes. Unlike surface coatings that wear away, cryogenics harden to the core by minimizing soft metal (austenite) and creating more hard metal (martensite). The result is a product that is more consistently hard throughout, resulting in life up to 50% longer than the competition. Milwaukee Ice Hardened hole saws also feature Matrix II bi-metal construction for greater durability and a unique precision-ground tooth geometry for faster cutting. A positive rake angle cuts more aggressively while deeper gullets quickly remove chips. A radiused back face reduces stress on the teeth, ensuring that the blade delivers optimum life and speed. Functional slot geometry allows for a standard slotted screwdriver to fit completely underneath the plug for easier plug removal.