Abstract: An annular-gap seal for a valve, blocks the fluid flow from a high-pressure side to a low-pressure side. The valve has a cylinder, through which the fluid flows and in which a piston is axially displaced. In the blocked position, an annular gap between the piston and the cylinder can be sealed by the annular gap seal, which lies in a groove that runs around the cylinder. To increase the sealing action of the gap seal, two sealing rings lie adjacent to one another mirror-symmetrically in the groove. In the blocked position, fluid from the high-pressure side causes a sealing lip of a first sealing ring that faces the low-pressure side to be pressed in a fluid-tight manner against the piston and a sealing face of the first sealing ring to be pressed in a fluid-tight manner against the wall of the groove.