Wheelchairs , driven by the occupant himself or by another person who rotates the rear wheels by pushing the rings attached to the outside of these. They are manufactured in two models mainly - folding (to save space and be able to be transported in luggage racks and other similar rooms) and rigid . Many of both models are made of ultralight materials, such as aluminum aircraft and carbon titanium with a Kevlar coating to provide greater durability, and especially lightness, since its user should be able to lift and store it, thus achieving a certain degree of autonomy and self-sufficiency.