HPI 18' Round SUN BLOK Swimming Pool Black Solar Blanket For Mesh Winter Covers 2 For 1 Solar Blanket - Designed to prevent algae from growing during the Winter months & helps retain sunlight in the Spring and Summer Lay bubbles down and flat on the surface of the water before installing your mesh winter cover Your pool will look cleaner when you open it in the Spring & Help Retain Sunlight in the Summer Note: Item ships directly from the manufacturer so please allow 6 to 7 business days to receive