The Harmsco HB-20-0.35-W removes sediment, silt, dirt, rust, and other particles to the 0.35 micron level.The Harmsco HB-20-0.35-W Pleated Water Filter Cartridge is a 20″ x 4.5″ sediment filter that will fit in most big blue housings. The Harmsco HB-20-0.35-W Pleated Water Filter Cartridge offers a micron rating of 0.35 and a flow rate of 26 gpm.