Four different herringbone gears:
0.5 module - 16 and 25 teeth.
0.7 module - 10 and 22 teeth.
1.0 module - 8 and 16 teeth.
1.5 module - 8 and 12 teeth.
The offset for the pegs are 0.1mm, so you might have to sand them a bit depending on your printer.
The author hasn't provided the model origin yet.