The Vevor pool cover water bags are designed to help secure an in-ground pool cover during winter and reduce debris, wind, and rain intrusion. This 12-piece set features a dual-chamber design for added stability and reduced rolling in strong weather. Made from 0.4 mm PVC with high-frequency welded seams, the bags are built for leak resistance and seasonal outdoor use. Each bag includes a twist cap with a rubber gasket for easier filling and a tighter seal. The long 10' format helps provide reliable ballast around the pool cover perimeter.