Gearbox is a part, that makes any powered wheel (suction cup/normal) go backwards/reverse. Similar to a motor, it can only be placed inside of a metal/wood box. They have 4 different skins, some including Golden, Bone, and Steampunk. Even when the box it resides in is damaged, it will not fall out similar to motors. Gearboxes are unique in that (along with motors) they do not do anything when alone, but when paired with another part (powered wheels) they compliment the part.