The HCE0.5-20S1S Shelco MicroVantage HCP series is a high capacity polyester pleated cartridge Filter that is 90% efficient. The polyester media is rated with a 0.5 micron retention rating. This filter has a nominal length of 20 inches and has a S1 = Double Open Ends. The filter has a S = Silicone gasket material. FDA listed materials: All materials comply with FDA CFR criteria for food & beverage contact. Optimize for retention and excellent flow rates. Maximum operating temperature is 176*F (80*C). See specification sheet for additional details. This product is made to order and is non-returnable.