Suitable for all existing Bestway sand filters Provides an even more efficient way to filter your pool than sand - 1.10 lbs (500 g) of flow clear polysphere is equal to 39.68 lbs (18 kg) of sand This long life product also provides high filtration - clean and clear water is reached in less time Much lighter than sand - easy to carry and transport - less fuss to keep your pool in tip top condition 100 percent recyclable and non-toxic PET material - you can even wash the filtration balls by hand.