Designed using low-cost, environmentally-friendly materials, the filter bags provide a greater retention efficiency, operational integrity and reliability. The bags feature a molded top ring seal and all-welded construction of new needle felt media - made from recycled fibers containing no optical white additives. Singed on the outside for maximum stability and prevention of fiber release, the bags feature high strength welded construction on the side and bottom. The patented ring on the top provides optimum sealing and eliminates bypass common with snap ring designs. The filter bag also reduces process system contamination caused by debris passing through needle punch holes or around sealing rings found on other bags. The bags are available in both polypropylene and polyester media construction to fit and seal most industry standard Number 1 (7-inch x 16-inch) and Number 2 (7-inch x 32-inch) size bag vessels.