Gears are incredibly useful – they can be used to create custom gearboxes to transfer motion, change output shaft speed, increase torque, and any number of other gear like functions. Different types of gears have different purposes and this kit has a great assortment of regular gears, crown gears, worm gears, double reduction gears and a linear gear. The kit also contains assorted pulleys – these allow for smoother motion and more efficient transfer of movement. In total, the kit has 106 pieces – perfect for a wide range of applications.