This is a Centertrack cog like the
other, except without the side flanges. Absent the flanges it is less strong, and is thus intended for stainless steel printing only.
The printed stainless steel part did not fit on the hyperglide splines -- the dimensional accuracy of stainless steel is a bit unpredictable. A small amount of filing should do the job. But in the meantime the plastic printed part (with flanges) fits and appears to be working well. It is also about one-third the weight!