Single socket lamp

The lamp e.g. metal halide lamp (10), has a bulb surrounded by a casing part. A socket includes a socket piece (12) with a central opening, in which an outer bulb (7) is taken up. The part has a circular opening with a radially protruding edge that includes upper and lower contact surfaces with respect to the socket. The part is fastened to the piece by a glazing-free mechanical retaining mechanism. A damping unit (1) is attached between an enveloping bulb (3) and the piece. The damping unit is formed as a ring cut out from a panel, where the ring has a bar socket at two opposite sides.