Heat Retention: Round cover can not only effectively prevent water evaporation loss, but also maintain the water temperature and absorb the heat energy of the sun's rays to heat the water, reducing the time you need to heat the water next time. Filtration: Energy saving lid for hot tub can effectively keep out wildlife and any lingering debris. It can also play a role in preventing dust, reducing condensation and freezing on the . Simple to Inflate: Due to the fast and simple inflation speed of this hot tub cover, it can be used within a few minutes to keep the hot tub clean and warm. 4.5 Feet Diameter: The inflatable hot tub cover has a diameter of 4.5 feet, which are compatible with most of our spa hot tub series. Reduce Maintenance: This lid ensures that tub maintenance is minimal, while the cover prohibits items from the entering the water it also cut downs on the number of filters used.