MarinelandMagnumPolishing Internal Filter Rite-SizeJH Floss Sleeves fit the Marineland Magnum Polishing Internal Canister Filter. The JH Floss sleeve is designed with fine mesh to trap and hold dirt particles. The open cell construction promotes water flow without impairing overall filter performance. The Marineland Magnum Polishing Canister Filter Floss Sleeve should be changed monthly for best results.