This is a classic device for demonstrating mechanical advantage and the conservation of energy. It consists of a single stepped wheel with four coaxial steps of 35, 50, 65, and 105mm diameter. The wheel is supported on a steel rod by a ball bearing. Additional Info: This is a classic device for demonstrating mechanical advantage and the conservation of energy. It consists of a single stepped wheel with four coaxial steps of 35, 50, 65, and 105mm diameter. The wheel is supported on a steel rod by a ball bearing. Package Size(L x W x H): 12.5 X 5.5 X 18 (IN) Categories: Mechanics, Supplies HTS Code: 9023.00.0000 UNSPSC: 6.01e+007 Country Of Origin: CHINA