A method of manufacturing a sealing element for use in a fluid conveyance device comprising the steps of: forming an elastomeric sealing body including a first body portion defining at least one annular sealing rib, and a second body portion arranged on an end of the first body portion, the second body portion comprising an annular protrusion extending radially beyond the first body portion; and forming a layer of barrier material on a free end of the second body portion, wherein the forming steps are carried out in a single molding operation.