The WGPS Series filter cartridges are polysulfone membrane filter cartridges and are perfect for economical applications. The highly asymmetrical polysulfone membrane is ideal for water-grade applications requiring absolute retention at an economical cost. Constructed of FDA listed materials and meet USP Class VI Biological Test for plastics with membrane ratings from 0.03 to 1.0 microns. The asymmetrical surface enhances flow rates and extends service life.