The DERBIGUM proven performance at an exceptional value. It is manufactured from a unique blend of APP (atactic polypropylene) polymers and select asphalts that enhances the weathering capabilities and UV resistance of the membrane. Reinforced with a heat resistant non-woven polyester mat which provides the strength and durability necessary in a roofing membrane. Adapts well to the use of aluminum or other fine coatings. Membranes are film-backed for ease of heat-weldeing installation.