White plastic circular wheels with teeth around the rim and a central hole; designed for timing belts or chains in power transmission systems. The left bin appears to have sprockets with more rounded teeth suitable for roller chains, while the right bin has pulleys with trapezoidal teeth for timing belts. Likely made from nylon or acetal for durability and low friction.
Diameter 25-150 mm (1-6 inches), width 10-30 mm, bore (central hole) 5-12 mm (3/16-1/2 inch).
