Facing improves the alignment of bearings in the headset, giving a better fit for improved strength and durability
The 690-XXL has an approximate diameter of 65mm and is a larger version of the 690 and 690-XL facers for facing 1.5"" head tubes with low profile Zero Stack type headsets
Must be used with the 55.9mm 790 pilot to ensure the frame is reamed and faced accurately