Won't split like water bags! These rugged polyethylene tubs are made to stay flexible down to 50°F below zero. Will not crack or leak in the coldest weather. The blocks come with a secure snap-lock cover and are U.V. treated to last for years. Unique nesting design allows for easy storage. Each Aqua Blok measures 3' L x 8' W x 4' D. Hold your cover firmly in place with Aqua Bloks! 5-Year Warranty.