As rough as it gets, our fiberglass reinforced plastic (FRP) cover is made for heavy snow loads or larger spas that need the added security of the strongest cover available. On the outside, the Ultra cover has all the great looks of all our spa covers. On the inside, the Ultra cover’s foam inserts are sandwiched between layers of fiberglass reinforced plastic for unsurpassed strength. The Ultra cover features a five-year limited warranty.The Ultra cover meets or exceeds all A.S.T.M. safety standards.