Flow-Max HP Series Pleated Sediment Filter, 20 IN x 2 1/2 IN with DOE End Cap, 0.45 Micron This 9 3/4 IN x 2 1/2 IN, 0.45 micron Flow-Max HP series pleated sediment filter with DOE end caps is a high efficiency filter with a greater surface area than a wound, spun or melt blown filter.