Abstract: A valve element includes a valve body member formed of a rigid material, where the valve body member defines a front-to-rear extending longitudinal axis, and has a generally radially outwardly facing first contact surface of generally frusto-conical configuration tapering forwardly, and a radially inwardly extending annular recess disposed rearwardly of the contact surface. The valve body member further includes a sealing insert mounted on the valve body member which includes a generally radially inwardly projecting lip received in the recess, an axially forwardly facing sealing face, a radially inwardly facing second contact surface disposed between the sealing face and the lip which tightly engages the first contact surface to conform to the frusto-conical configuration thereof, and a seal abrasion gauge disposed upon an outer peripheral portion of the axially forwardly facing sealing face.