Replaces Parts: OEM# 178584, R173576, R173476 Unicel# C-7471 / C7471, C-7471-4, C-7471RA, Pleatco# PCC-105 / PCC105, PCC105-PAK4, PCC105-M, PCC105-M-PAK4, Filbur# FC-6470, FC-1977 / FC1977, FC-1977M, FC-1977P, Aladdin# 20503. NOTE: This is a compatible aftermarket replacement part made in the USA. The manufacturers' names and part numbers have been used for reference purposes only. Optimum Pool Technologies Inc is an independent brand. These filters are also compatible with the 425SQFT WaterWay Crystal Water Cartridge Filter!