Wikipedia
Monokote
MonoKote is commercially available light weight plastic shrink wrap film available in various color schemes with an adhesive on one side, used to cover and form the surfaces of a model aircraft. The material is cut to size and applied to the airframe surfaces using a hobby iron or heat gun. TopFlite Monokote covering film is made by General Formulations.
The name MonoKote, a registered trademark of model aircraft manufacturer Top Flite, refers to the fact that it is a one-step covering material to coat the surface of the model to seal the flight surfaces. The patent for Top Flite Monokote is held by Sidney Axlerod
Monokote is also a type of fireproofing material, which is gypsum-based and is spray-applied.