A method and apparatus for preventing unauthorized use of DVDs on a DVD ROM drive. The normally closed valve can comprise a circular valve seal face formed by the underside of a rim of an elastomeric valve boss and a circular valve seat, which is formed by the rim of a through-hole molded into, for example, a plastic cassette, such that the valve seal face, the valve seat, and the through hole are concentric. The ring insert is disposed in the radial gap and is bonded to the inner and outer circumferential components.