Abstract: An extruded radiant energy transparent cover used with solar heat collector assemblies, and made into modules that are retained in position with support members which securely hold the cover in place. The extruded cover panels are of preferably elongated side by side tubes molded with common walls. A support rib is aligned with each of the walls. Where two of the modules join, two support ribs are placed contiguous, and are held in the same support members as the single ribs. Thus the installation is simplified by the lack of necessity to provide special brackets for holding the modular sections together.