20 B PS GD 50 - 20" X 4 ¼" Big Gradient Density 50 Micron Polyspun
100 to 50 Micron Density. Suitable for all 20" Big Blue and Jumbo sized housings. Holds more dirt and impurities than normal Depth poly spun or pleated filters. Please note this filter is not a normal Polyspun Depth Cartridge it is the highest quality NSF approved Dual Gradient Density.