2-1/16" ICE HARDENED HOLE SAW Ice Hardened™ for up to 50% longer life than the competition Optimized tooth form for up to 2X faster cutting Functional slots for faster plug removal Matrix II bi-metal teeth for greater durability. 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.