Filter socks stay hidden out of the way in the sump, but they are a boon for clear aquarium water. Micron filter bags provide excellent mechanical filtration, which helps reduce the amount of ammonia-producing organic matter in your aquarium. They also help prevent larger objects such as sand, crabs, and snails from damaging pump motors. This new 3-in-1 package is more cost effective and convenient. You can have more choices to fit your filtration need