Used to demonstrate the concepts of force and mechanical equilibrium. Contains a 5 1/2 × 9 3/4" laminated wooden base with a capstan mounted at one end and screw eye for hanging pulleys at the other, 24" vertical support rod, 8" crossbar with clamp, 8 single pulleys, 2 double pulleys, wheel and axle, 6 pulley clamps, 90° clamp, 9 hooked masses ranging from 10 to 1,000 g, pulley cord, and instructions.