Round Gasket O-ring, Teflon (TFE) Encapsulated Viton Material. Fits FSPN 255, FSPN 250-TFE-ENC-FSQ, 250-V-TFE-ENC-FSQ, 255-TFE-ENC-FSP, FSPN 255-V-TFE-ENC STD, FSPN-255 2 Bag Vessel. Ultra Chemical Resistant FEP-Encapsulated Viton Rubber O-Ring. EGR30011VT EGR-30011-VT EGR-30011VT EGR30011-VT