Abstract: A valve body has a closing member rotatably mounted in a passage for opening and closing said passage. An annular groove having a substantially dove-tailed cross sectional portion is formed in said valve body for receiving an elastomeric annular seal ring. Said groove is positioned so that the seal ring is engaged by the periphery of the closing member when said closing member is in the closed position. The annular seal ring includes a pair of annular axially extending arms disposed on each side of said seal ring and an annular spring member embedded in said seal ring and extending into the axially extending arms so that when the seal ring is disposed in the groove the spring member forces said arms into engagement with the dove-tailed portion of the groove thereby rendering the seal ring self-retaining.