For sale is this Park Tool 788 43.95mm reamer (for use with HTM-1). Brand new in original packaging. For use with the HTR-1 Head tube Reaming and Facing Set. The 788 reams the headtube to an internal diameter at 43.95 mm to accept internal headset cups with 44.05 mm - 44.10 mm outer diameter (1-1/8 inch ZS standard). If you have any questions then please feel free to drop me a message and I'll do my best to help.