Valve seat 45°cutter head 2 1/2 diameter(63.50mm)Approx. Range: 2.400″-2.600″(60.9-66.0mm) to be used with 3/8″ top Neway pilots, specially engineered for the “new3Acut 3 angle cut blades, to cut 3 angles in one pass! Serdi style 30/45/60 do all 3 angles with one cutter head, save time and save on tooling. This cutter head takes 7 blades (it can be used like a single angle cutter head), These cutters are to be driven by a powered machine when used with 3 angle profile blades, when used with serrated blades, a “T” handle can be used to drive cutters, made out of anodized aluminum, tool steel hub, black oxide finish. “Cam lock” holding screw, 1/2″ drive, requires 5 blades, 1/2″ long recommended. The listing is for one cutter head, blades shown on pictures are not included.