Felt Filter Socks for Red Sea Reefer and MAX series of tanks. Red Sea Felt Filter Socks are great for trapping detritus and free floating particles in your tank. Filter socks are washable for continued use and will help give your tanks water that crystal clear look. 225 Micron Felt Filter Sock 4\” x 10\” with Plastic Ring Filter socks are most commonly used in sumps to help trap free floating particles in the water that flows through the sock. The Red Sea felt filter socks are great for removing large pieces of free floating material from the water that flows through the sock. Felt filter socks are a thinner material than felt usually lasting a bit longer and easier to clean. We do recommend having a few extra socks on hand and changing them ever couple days for best results. The Red Sea filter socks have a 225 micron rating to allow a majority of detritus to be collected while allowing smaller particles through. We have found with filter socks with a micron size below 150 can clog very quickly, where 200+ micron socks can last a few days before they are clogged. Compatible with Red Sea Reefer and MAX-S series of tanks.