A valve for sealing the hub of a sheath assembly is provided. The valve includes a valve body having a solid thickness extending between a proximal surface and a distal surface. A bisecting slot extends across the proximal surface of the valve body and terminates at a depth less than the thickness of the valve body such that a portion of the valve body distally of the slot defines a bridge extending between opposed halves of the valve body such that the distal surface of the valve body is substantially continuous and a central portion of the proximal surface of the valve body is concave and defines a concave proximal portion.
