Description
note:
The middle length of all models is 12 cm.
The middle diameter of 61 cm is 25 mm, and the diameter on both sides is 19 mm.
65 cm 23 teeth, the middle diameter is 25 mm, the diameter on both sides is 22 mm.
There are 28 teeth of 65 cm/71 cm/74 cm, the middle diameter is 30 mm, and the diameter on both sides is 24 mm.