Zhenxing® Polypropylene bags are made with a glazed finish to prevent fiber migration, while Polyester and Nomex bags are singed. This material will low cost and is most widely used  in Cement / Chemical / Food processing /  reverse osmosis·Silicone-free construction·High dirt holding capacity·Ability to remove both solid and gelatinous particles·Low cost·Glazed/singed finish reduces fiber-shedding  All seams and the collar are sonically welded, enhancing filtration quality, eliminating leaks and bypass that may have occurred with sewn seams.