This handsome looking metalworking fluid filtration system claims to remove contaminants as low as 1-micron. Clean down to that level will not only increase fluid life, it will increase machine  and tool life.  The operation of the portable Harvard filter system is patented technology.  The filtration makes the difference. The Harvard^TM filter is a design with a multiple element filter. The non-channeling seal forms a positive barrier to channeling. The flow of oil carries the contaminants into the depths of the filter media with no flow restrictions from surface loading. Each element will remove water from wet oils. The hydraulic pressure of the oil compresses the layers of filter media against the patented non-channeling seal and toward the center of the element creating a constant pressure to avoid channeling. This compression along with the pressure against the filtering surface of the element causes the elements to become more compact, trapping contaminants as small as one micron. The link explains it much better with a diagram.  See also U.S.. Patent 7,938,971. I looked them up on the USPTO website, and I think this is it.  (Hey Harvard, didn't your lawyers tell you to put that number on the brochure?)  This is a very interesting machine and certainly passes the eyeball test for well-built.