The 758.2 is used in conjunction with the Park Tool HTR-1 Head Tube Reaming and Facing Set to ream head tubes that use the 1.5" external cup headset standard.
Features
Sized for 1.5" external cup headsets
SHIS: sized for EC49 upper and lower head tubes
Reamer diameter: 49.57 mm
Reamer depth: 25 mm
Facer diameter: 62 mm
Requires use of the 750.2 Centering Cone Adaptor
NOTE: Always use cutting fluid such as Park Tool CF-2 when machining.