BeyondNice Hot Tub Cover and Spa Cover, 4-inch Feel confident - This Basic hot tub cover is 4" thick for the cost conscious buyer not looking for maximum insulation. Buy directly from the manufacturer here, pay wholesale and save your time and money. Feel secure - we have made ASTM compliant replacement covers for 30 years and deliver via freight directly to your residence. Feel safe - our hot tub covers are backed with a 5 year warranty, including water logging and no need to return your cover. Spa covers can have sloping tops for rain run off or be flat for protected areas such as under a deck. This cover is 4 inches thick, tapering to 2. Thicker insulates better. Create a cover suited exactly to your needs with our exclusive Design-Your-Own ordering. Specify the insulation and strength you need.