Starrett dual pitch professional hole saw. Hardened, heat resistant, positive rake HSS teeth with alloy backing. Strong and shatter resistant. Economically cuts wood, metal and steel. For hand held or fixed drills. 1-5/8-inches cutting depth. Aggressive material penetration and swarf clearance, removing the need to carry a constant and variable pitch hole saw. Constructed of hardened steel and abrasion resisting high speed steel teeth with a tough alloy body and cap. The complete multi-purpose saw. Dual pitch professional will cut a wide range of materials, regardless of thickness. Starrett designed tooth geometry resulting in huge improvements in chip flow. Smooth cut with minimal tendency to bite or snag when cutting thinner gauge materials. 4-6 teeth per inch (25-millimeters). 1-1/8-inches diameter. A1 or A4 arbor type. 1/2"-20 thread size.