Maximise your time enjoying your pool instead of cleaning it, by keeping leaf litter and bugs out and reducing the chances of your filter clogging with this 500 micron pool cover. Reduce Evaporation By Over 97% Genuine 500 micron technology means your pool cover will last longer than the thinner ones on the market. Plus it will provide greater heat retention and will be more effective in reducing water evaporation - by up to 97%!! Save Water Save On Chemicals Reduce your rate of evaporation and you'll also reduce the amount you spend on chemicals for your pool. Win-Win situation! These heavy duty covers are made from the highest quality material LDPE which is salt, chlorine, and sun resistant.