Keep your in-ground pool cover securely in place all winter with these heavy-duty pool cover water bags. Designed to weigh down the cover, they prevent strong winds from shifting or removing it, ensuring your pool stays protected throughout the off-season. Made from 0.4mm thick PVC (27 gauge)-twice as thick as standard options-these durable water tubes feature patent-pending sealing technology, making them 100% leakproof and airtight for long-lasting performance. Built to withstand extreme weather conditions, these pool cover weights can handle temperatures as low as −10°F (−25°C) and as high as 180°F (80°C), making them ideal for any climate. For easy filling, they feature extra-wide valves that connect to a garden hose, while grippy leakproof twisting caps ensure a mess-free, secure seal-far more convenient than snap-on caps. Their dual-chamber design keeps them stable, preventing rolling and ensuring they stay in place. As part of the Premium Sapphire Series, these pool cover water bags are USA-CPSIA compliant, tested by an accredited lab, and free from harmful chemicals and dangerous metals. Keep your pool protected, clean, and winter-ready with this reliable winterization solution. Color: Blue.