"PBI .500in Offset Transmission Sprocket - 23T CNC-machined from a premium nickel, chromoly steel (8620), case-hardened and finished with an electroless nickel plating for corrosion/wear resistance and lubricity Sprockets are drilled and tapped to accommodate late-model lock plate, PART #TPR 100, available separately Will also fit 86-93 Big Twin models with use of OEM #33344-94 (spacer), OEM #12067A (seal) and OEM #11165 (O-ring) Offset measurement is taken from the face that rests against the mainshaft bearing to the inside of the teeth for Total Offset description For use with .530 pitch chain