This Blue Wave 8 Water Tube provides good protection for a pool. It weighs up to 33 percent heavier than most other brands of bags. Use this Blue Wave water tube to hold down the edges of a pool cover. It s made of heavy-duty material to prevent splitting. The valve can be easily filled with a garden hose and is designed not to leak. Keep it handy in the winter months or during rough weather to keep the pool cover safe from wind rain and snow.