Polyester gelcoat. Show/Hide the details of the product Sprigel PX 10166 is an unsaturated polyester resin based gelcoat. It is specifically formulated to attain high adherence with epoxy laminates. The resulting hybrid laminates combine the high mechanical properties of epoxy laminates with the surface quality of a polyester gelcoat. It is used in the construction for gliders, planes, automobiles, windsurfers etc...