Pro Clear Aquatic Systems Fabric Filter Stock 200 Micron Aquarium Filter Media is available in a 4X7 inch and 7X12 Inch option, these high-efficiency aquarium filter socks are designed to trap fine debris and particles from tank water. Made from durable 200-micron mesh, This 7-inch filter sock fits compatible sock holders while the 4-inch diameter sock works with standard filter holders and sump systems to polish water clarity and improve overall filtration. It’s easy to install and replace, helping maintain a cleaner, healthier aquatic environment by removing waste before it can break down and affect water quality. Available in Multiple Sizes