Are you still worried about not finding suitable filter balls? Our filter balls are made of sponge, which can be used for a long time and are not easily . They are good choices to filter and clean the swimming pool. Features -Color:White -Material:Sponge -Size:7.00X7.00X7.00cm/2.75X2.75X2.75in -Forming a rapid filtration rate, washable and elastic, you can squeeze the out of the sponge ball and clean it after use. -Light weight, high strength, stable physical and chemical items, durable. Reusable descaling sponge balls are widely used to clean swimming pools, tubs, sinks, spas and more. -With the flow of , the filling gaps becomes larger and less likely to be blocked. -Large specific surface area, strong activity, good effect. Being reusable to save money and effort. -Fine workmanship and creative appearance ensure its popularity and practicality. Package list: 4 x Filter Balls