Features:-Filter balls are made of polyethylene and modified fibers. Good elasticity, non-toxic, good stability and good filtering effect.-Regular cleaning, machine washable, recyclable, very durable and low shedding. (Note: put the filter ball into the laundry bag, machine washable.)-The fibers floating with the water make the gaps between the fillers variable and difficult to be blocked by biofilm.-Suitable for filters such as filter ponds, filter buckets and swimming pools, which can effectively filter fine suspended particles and improve water quality.Specification:Material: 100% polyethyleneDiameter: 50mmWeight: 1400g, can replace 50kg filter sandDensity: 1.45g/cm³Porosity: 99%Colour: black Package Included:1x Pack of 1400g Filter balls .