Four (4) Pack of Filter Cartridge Elements for the Clean & Clear PLUS 520; 125/130 SQ.FT. pool filter. Manufactured by Optimum Pool Technologies with the highest quality materials for easy cleaning and long life. Replaces OEM# 178585 , r178585 , Unicel# C-7472 cartridges / C7472 cartridges, Pleatco# PCC-130 / PCC130, Filbur# FC-1978 / FC1978