Making sure that your pool filter is working properly is one of the essential ways to keep your pool sparkling clean. This includes replacing the filter cartridges as needed. Optimum Pool Technologies manufactures a 4-Pack of high-quality filter cartridge replacements for Pentair’s® Clean & Clear® Plus 520. Each of the four cartridges contain 130 square feet of pleat material to total 520 square feet of filtration. Need to replace just one of your cartridges? We also carry a single Cartridge Replacement For Clean & Clear® Plus 520 by Optimum Pool Technologies. Features: Made in USA with 100% Reemay® filtration media that was made specifically for durability and cleanability. Replaces: Pentair® CCP520 Cartridge (Filter PN 160332), Waterway® Crystal Water® 125 SQFT (817-0131) Outside Diameter: 7” Inside Diameter: 3" Length: 32-1/16” Replaces Parts: OEM# 178585, R173578, 817-0143 Unicel®# C-7472/C7472, C-7472RA, Pleatco®# PCC-130/PCC130, PCC130-M, PCC130-PAK4, PWW130 Filbur®# FC-6475, FC-1978/FC1978, FC-1978M, FC-1978P, Aladdin®# 22505 Includes support bands around each cartridge element. Note: Four 125 sq. ft./130 sq. ft. cartridges required. Model dated after 11/98.These filters are also compatible with the 525SQFT WaterWay® Crystal Water® Cartridge Filter! Only need to replace one filter cartridge?Check out the single Cartridge Replacement For Clean & Clear® Plus 520 by Optimum Pool Technologies!