UNIBAG filter bags provide the value and reliability of a high performance filter bag seal, fully welded construction, the economy of a typical sewn construction and the social commitment to using environmentally friendly materials. They are manufactured from needle felt material, without optical white additives or bleaching agents. They comply with the industry standard for bypass-free filter bag construction and are available in polypropylene and polyester. Polyester material uses at least 40% recycled fibers.