This easy to use pool cover is made from a high tech, exclusively blended, micro mesh fabric that stops leaves from getting in, but allows rain water through. It has a generous overlap of 400mm (15′) and a marine grade stretch cord threaded through grommets sewn into the hem for easy fitting. The cover simply stretches over the pool top rail like a big shower cap!. The grommets are fitted at 400mm (15′) spacings so you can tie down the cover if you want to use it with a pool cover float.