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. This is an 800 micron, size 01 Eaton filter bag with description: NMO-800-P01E-50. All SENTINEL filter bags are welded, not sewn. This makes sturdy seams that prevent bypass and eliminate needle holes and loose fibers. This bag is made of Nylon monofilament with a plastic Polypropylene ring. Comes in box quantities of 50.