Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. A Casterboard, also known as a Waveboard, is a two-wheeled, human-powered land vehicle that is closely related to the skateboard and the snakeboard. Two narrow platforms known as "decks" are joined by a "torsion bar", which consists of a metal beam, usually coated by rubber, that houses a strong spring. One polyurethane wheel is connected to each deck with a caster so that that each wheel can steer independently, and each caster has a steering axis that is tilted about 30° back from the vertical.