This Milwaukee® quick-change arbor with cobalt pilot bit, is designed to optimise the performance of the HOLE DOZER™ with Carbide Teeth hole saw. The cobalt pilot bit provides 10X longer life than standard HSS pilot bits, matching the performance of the HOLE DOZER™ with Carbide Teeth hole saws when drilling through the toughest materials like stainless steel, cast iron, wood with nails, thick metal & abrasives. The pilot bit's 135° split point tip engages on first contact and the quad edge tip decreases heat build up helping you cut faster. The hardened steel arbor features an adjusting nut mechanism to secure the hole saw tightly onto the arbor for reduced wobble and accurate cuts. The arbor shank is compatible to our 7/16" Milwaukee®QUIK-LOK™ extensions.