Fiberglass is finespun filaments of glass, which are available in a rope or mat form. When used in a process with polyester resins, catalysts and hardeners, can be formed or molded into pools, spas and related shapes. It is a very tough and durable plastic material consisting of extremely fine glass fibers, used in making various products, such as yarns, fabrics, insulators, and structural objects or parts.

Properties
Fiberglass films have many unique and outstanding properties, which provide design opportunities for the improvement of existing products and the developments of new products. It resists most acids with the exception of hydrofluoric acid and hot phosphoric acid. It has dimensional stability, will not shrink or stretch with change in atmospheric conditions. Fiberglass film has low coefficient of thermal expansion and relatively high thermal conductivity. It had high dielectric strength and relatively low dielectric constants. It also has low water absorption and high temperature resistance. It is used for harsh, wet insulation jacketing application.