Hole Saw Arbor, Arbor Type Standard, Thread Size 1/2 In.-20, Arbor Shank Style Hex, Arbor Shank Size 3/8 in, Fits Hole Saw Dia. - Imperial 9/16 in to 1 3/16 in, Fits Hole Saw Dia. - Metric 14 to 30 mm, Pilot Bit Shank Style Hex