The Vevor pool filter balls are designed to replace traditional pool filter sand with lightweight, reusable blue polyester fiber media. They provide fast, efficient filtration to capture fine debris and help restore clear water in pools, aquariums, and fish tanks. These filter balls are compatible with sand filters, cartridge filters, and DE filters for versatile use. A wash bag is included to support easier cleaning and maintenance. Built for repeated use, they offer a durable and convenient filtration solution.