Clearwater Spas fully-insulated covers are the best you can buy.

Clearwater Spas fully-insulated hardcovers are tapered from 3″ on the ends up to 5″ in the middle to assist with rain and snow drainage.  Insulation rating R-18 value.  Quality made with virgin foam cores, marine grade vinyl, full-length heat seal gaskets.  UL Classification for ASTM Safety.  Child safety locks.  Made in the U.S.A.

Colors: Gray, Walnut, and Black