54 millimeter non-arbored speed slot- easy to use plug removal slot 10 percent taller than prior generation for deeper cut non-binding coating for faster cut T2 technology up to 2x life. Reinforced to cut stronger, last longer and resist tooth strippageThick backing plate with holes for drive pins resists damage due to high torqueHigh speed steel teeth resist breaking and offer extended lifeBi-metal2-1/8 in. diameterUse this hole saw with a 2L, 3L, 6L, 7L standard arbor or a 2L, 6L snap-back arbor.