Original 56-72 factory fiberglass panels were produced in molds that created a smooth surface on both the top and underside of the panel. To help keep your Corvette "all original", Zip offers as many press molded panels as available. Panels are manufactured to higher quality standards than hand laid panels using fiberglass and resin placed inside male and female molds, pressed together under high pressure and heat to ensure consistent thickness. Original panels are white, gray or black in color depending on year and do not have a gelcoat surface. Press molded panels require the use of bonding strips when installed.