The Aquapro Mega Quad 425 In-ground Cartridge Pool Filter Tank is a low-maintenance filter system with high-powered performance. Filtering particles as small as 20 microns, the Aquapro cartridge filter is designed with four cartridges (included) which maximize the amount of dirt and debris captured. Aquapro’s compact designs, along with maximum filtering capability, will reduce maintenance time needed. Aquapro’s advantage is our superior designs & maximum hydraulic flow working in unison with the filter element for efficient performance.