Park Tool Facing Pilots. Features: Oversized headset facing pilots for PK-6710 (HTR-1 tool set) PK-6731 (#767) used when facing 1.5" head tubes with an ID of 49.5mm, including those with an hour glass shaped head tube PK-6732 (#768) designed for headtubes with an ID of 43.8mm that use a low profile, zero stack or internal headset PK-6733 (#790) used when facing head tubes with 55.90-55.95mm ID for 1 1/2" zero stack or internal headset Specs: Description:facing pilot, #768 - 43.8mm Remarks:Use with PK-6730 (#690-XL facing cutter) & PK-6735 (#750 centering cone)