A seal has a core ring that is corrugated and a resilient material is attached to one or both of the top side surface and the bottom side surface. There is at least one corrugation on the top side (a convex corrugation) and at least one corrugation on the bottom side (a concave corrugation). The corrugations have sharp peaks and are shifted out of phase. A grommet around the inner diameter deters extrusion of the resilient material into the sealed system, and a folded over portion on the outer diameter helps deters extrusion into the environment.