A lampholder for shrouded low-wattage metal halide lamps which include a contact button on an extension of the lamp base to distinguish them from unshrouded lamps. A hub with walls and top is placed about the entrance to an additional cavity in the lampholder body. A socket contact is arranged to only make contact with the contact button at the end of an extension which is able to enter the cavity and not make contact with a contact button not an extension which is prevented from entering the cavity.