This Eisco Labs set contains five high-quality plastic single pulleys, each with a 50mm diameter and mounted on a steel frame with hooks at each end. Each pulley has a 4mm inner gap, an overall length of 8.9 cm, and is rated to hold over 50 lbs. Ideal for physics classroom experiments investigating Newton's Force Laws, mechanical advantage, and simple machine principles. The five-pulley set supports a wide variety of single, fixed, and movable pulley configurations.