Catalina's original white gasket was a vast improvement in material. But it was taller than it was wide (9/16 high X only 1/2 wide X 17' long) which made it prone to "falling over" when compressed by the hatch. Our new gasket is wider than it tall (5/8" high X 3/4" wide X 25' long) and is therefore more stable when installed. The increased width provides a more positive seal to the deck flange. Unlike weatherstrip material typically found in a hardware store, this foam is a closed cell EVA foam which won't absorb water. It is much higher density than the hardware store variety as well, providing a more positive seal. Used on all Catalinas built before the introduction of a gasket that lives in a groove in the deck flange. It is secured on its 3/4" self adhesive side to the underside of the hatch or pop top.