In 1993, our spa covers were first tested by an independent lab to gauge its compliance with the ASTM Safety Standard. All models passed and Sunstar was the first spa cover manufacturer to offer a safety-labeled cover. In 1994, Sunstar was the first to receive UL Classification and our covers are classified for ASTM Safety on all sizes, densities, and models, even swim spas. We are proud to offer the UL Classification mark on our covers,and you can be confident that Sunstar builds a spa cover that is favored by safety code officials nationwide.