Proper frame preparation is very important. Park Tool's Head Tube Reaming and Facing Set combines reaming and facing of the head tube to create a perfect fit for most sizes of head cups. Includes: - 30.1 mm reamer (part #751.2) and four different size pilots (29.8mm, 30.0mm, 33.8mm, and 36.8mm) - 690 facer - Quick-release, quick-adjust feature: bottom portion slides off and on easily without threading SHIS terminology: The HTR-1 as stock will face frames of EC29, EC30, EC34 and EC37. It will ream frames of EC30. Accessories will allow service in other standards.