Glycerin. Glycerin is an ingredient that can be found in many beauty products because of its moisture locking properties. It is a form of sugar alcohol that is available naturally in vegetable oils and can also be the byproduct of soap making.
Definition of wheel and axle : a mechanical device consisting of a grooved wheel turned by a cord or chain with a rigidly attached axle (as for winding up a weight) together with the supporting standards
A truck axle is a component in the drive system of any truck; it is essentially a link between wheels, and it can either be fixed to the wheels and rotate with them, or it can be fixed to the frame or other components of the vehicle, allowing the wheels to rotate around the axle.