This is an Eaton SENTINEL filter bag, description PE-100-P02H-WW-30. In Eaton nomenclature that means this is a 100 micron filter bag, size 02, made of polyester felt with a SENTINEL polyester ring. The bag has welded seams which are exceptionally strong and prevent bypass. This is an improvement over sewn seams which allow for bypass through needle holes. The ring at the top of the bag snaps into place inside your filter housing and features a sealing lip that activates with increases in differential pressure.