These jumbo sized pulleys are designed for classroom demonstration. The single, double, and triple pulleys are all 70mm in diameter. The pulleys are "open" type so users can run pulley cords through them more easily. Lightweight, low-friction, and deformation-resistant plastic ensures accurate results. Additional Info: These jumbo sized pulleys are designed for classroom demonstration. The single, double, and triple pulleys are all 70mm in diameter. The pulleys are "open" type so users can run pulley cords through them more easily. Package Size(L x W x H): 7.5 X 5 X 3 (IN) Categories: Mechanics, Pulleys HTS Code: 8483.50.9080 UNSPSC: 3.11718e+007 Country Of Origin: CHINA