The SENTINEL line of filter bags by Eaton was designed for bypass-free construction. It features all welded bag seams and a pressure sealing ring that make for an effective and efficient filter bag. NMO-150-P03E-50is the bag description of a size 03, 150 micron filter. All SENTINEL filter bags are welded, not sewn. This makes sturdy seams that prevent bypass and eliminate needle holes and loose fibers. Made of Nylon monofilament with a Polypropylene SENTINEL ring, this bag comes in box quantities of 50.