Manufacturer No. - 49-56-0173 UPC - 045242193332Hole Saw Diameter: 3 in. Product Type: Hole Saw Blade Material: Bi-Metal Cutting Depth: 1.625 in. Arbor Type: Round Minimum Chuck Size: 3/4 in. Arbor Included: Yes Length: 1-7/8 in. Shank Diameter: 1/4 in.Ice Hardened for up to 50% Longer Cutting Than the Competition Optimized Tooth Shape for up to 2x Faster Cutting Functional Slots for Faster Plug Removal Matrix II Crown Teeth For increased 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 hardens to the core minimizing soft metal (austenite) and creating harder metal (martensite). The result is a product that is more uniform throughout, resulting in up to 50% longer hardening life than the competition. RPM Mild Steel: 115 RPM Stainless Steel: Aluminum: 55 RPM Cast Iron: 75 RPM 170Ice Hardened for up to 50% Longer Cutting Life Than the Competition Optimized Tooth Shape for up to 2X Faster Cutting Functional Slots for Faster Plug Removal Matrix II Crown Teeth For increased 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 hardens to the core by minimizing soft metal (austenite) and creating harder metal (martensite). The result is a product that is more uniform throughout, resulting in up to 50% longer hardening life than the competition. RPM Mild Steel: 115 RPM Stainless Steel: 55 RPM Cast Iron: 75 RPM Aluminum: 170