Eshopps Inc. 200 Micron Bag - 7 in. diameter x 17 1/2 in. Round Filter Bag, 7" x 200 MB. Provides excellent mechanical filtration, which helps reduce the amount of ammonia-producing organic matter in your aquarium. Helps prevent larger objects, such as sand, crabs, and snails from damaging pump motors.Perfect for larger sumps or those wanting to change filter socks less frequently.