Thermal Foam Spa Blanket.Designed to float on the water's surface, The Thermal Foam floating spa blanket is lightweight and durable it protects and extends the life of your spa insulating cover while significantly reducing heat loss and chemical evaporation consumption. Blue in colour and made of 1 8" thick closed cell polyethylene foam, these blankets are easily cut to size, and much more resistant to "bunching up" than the bubble blankets. Sold in 8 x 8 easy to cut to fit