This premium cover ensures that tub maintenance is minimal, while the cover prohibits items from entering the water and reduces the number of filters needed to remove debris. Floats on top of the water to help maintain heat of water when not in use. Inflatable bladder provides better heat preservation and rain outflow. Put the bladder onto the spa pool underneath the cover. Fits 4-6 Person Dellonda Hot Tub/Spas DL17 and DL24. PREMIUM QUALITY - Ensures minimal maintenance of the hot tub, while the cover prohibits items from entering the water. EXTRA LAYER OF PROTECTION - Reduces the number of filters that are needed to remove debris. HEAT RETENTION - Floats on top of the water to help maintain heat of water when not in use. INFLATABLE BLADDER - Provides better heat preservation and rain outflow. Simply place onto the spa pool underneath the cover. SUITABLE FOR 4-6 Person Dellonda Hot Tub/Spas DL17 and DL24. Diameter: 165cm.