When ordering a hot tub cover the foam pound or density is related to the strength of the cover. BeyondNice offers three different strengths of foam for our standard covers. 1.0#, 1.5# and 2# foam are the options you will find when ordering your cover. The one pound foam is the standard foam included with the cover. The 1.5# and the 2# foam options are upgrades, and very important ones to consider when ordering.