It has 255 teeth
The author remixed this model.
This is a GT2 belt version of the collar gear for the circular sock knitting machine.
It replaces the original collar gear if you want to drive the machine with a motor instead of the manual crank.
Functionally it’s the same part, but with gt2 teeth on the outside so it can be driven by a standard GT2 timing belt. This makes it easy to hook up a stepper or other motor.