High quality material - The filter balls are made of polyester fibres with high filtration strength, good elasticity and low loss. Pool filter balls are completely non-toxic and 100% recyclable!Perfect replacement for pool filter sand- The pool filter ball is designed to replace the filter sand for pool sand filters. 800g instead of 25kg of filter sand instead of filter sand and filter screen. Filter balls are 10 times more efficient than sand, is a perfect replacement for filter sand, filter glass and other media.Reusable and washable - Our pool filter balls can be cleaned regularly, are machine washable, recyclable, very durable and low loss. Unlike sand, the filter ball will not clog your filter and only requires less backwashing for mainte.