LTWHOME Medium Red Foam Filter Sponge Fit for Oase Biotec Screenmatic 18 & 36 Pond Filter Pack of 8 Medium Red Foam Filters Approx size:230mm x 150mm x 100mm. Custom designed and manufactured for the Oase Biotec Screenmatic 18 & 36 filtration systems. Provides efficient water flow with less clogging for long lasting filtration The more your purchase the best price you get.