Single M42 Cobalt Bimetal Hole Saw with 1-7/8" cutting depth. Uses a 1/4" Mandrel w/ round shank. Slotted sidewall for easier material ejection. Machined Solid Steel backing plate. Industrial Grade 8% Cobalt M42 ground Rugged Tooth Design excels in steel but will cut a variety of materials. Arbor Not Included.