Our dual chamber water tubes are constructed to last. These tubes are made with a durable heavy-duty vinyl that is puncture resistant. The advantages of the double-chambered tubes are that they will not roll and if one chamber springs a leak, the other will remain intact. The tube has a conveniently placed valve that makes it easy to fill with a garden hose and will not leak. These tubes will keep your pool cover in place all winter long. Only fill the tube halfway to avoid leaking caused by freezing water expanding.