This is a dual left hand helical metric gear molded of black thermoplastic material. There s an 8 mm wide 36 teeth 31.6 mm diameter section, and a 10.4 mm wide 28 teeth 24.7 mm section. The overall width is 19.55 mm. The bore is 8 mm with a flat all the way through the bore and with a tab extending an additional 2 mm beyond the face. Unused.
