Made of Evazote® foam, these pads are made with a unique high pressure nitrogen gas solution process. High quality extrusions and cross-linking of solid polymeric sheets are impregnated with pure nitrogen gas at elevated temperature and extremely high pressure. Then the impregnated solid sheets are expanded in a huge low pressure autoclave. This process results in an extremely regular and uniform cell structure in the foam. What this means to you is the foam is amazingly light and strong for its density. The pads are tough, flexible and resilient, and exhibit good UV stability. As a closed-cell foam, they will not absorb water.