Titanium Headtube
44mm internal diameter (slightly undersize, they need to be reamed after the frame is built to allow for proper fitment of headset)
4mm ridge on the end of the tubes to match up with ZS headsets - 50mm outer diameter
The tubes are relieved on the outside, and straight wall on the inside with no relief
Grade 5 titanium. They weld up nice, ream nice, and clean up very well. Nice headtubes for 44mm headsets
These work great for all ti bikes.