A lamp housing to be inserted into an installation-opening, comprising: - an outer surface and an inner surface; - a slot going through the outer surface into the inner surface; - a locking device connected to the outer surface, wherein the locking device comprises: - an elongated member; - a protruding part from the elongated member, wherein the protruding part, comprises - a bottom part; and - a top part, wherein the top part comprises a pushing-surface and a contacting-surface, and wherein the elongated member is able to pivot on a pivot axis between a first position and a second position such that: - in the first position, the elongated member is positioned such that the bottom part is inside the slot, and such that the top part is inside the housing, whereby the contacting-surface and the pushing-surface are inside the lamp housing; - in the second position, the elongated member is positioned such that the bottom part is outside the slot, and such that the top part is partly inside the slot, whereby the contacting-surface is contacting a part of the outer surface and the pushing-surface is between the inside of the housing and the outer surface, whereby the lamp housing is able to be wedged in the installation-opening by the elongated member, characterized in that the elongated member further comprises a part of the elongated member below the pivot axis, wherein the part of the elongated member below the pivot axis is thinner than a part of the elongated member above the pivot point. - an outer surface and an inner surface; - a slot going through the outer surface into the inner surface; - a locking device connected to the outer surface, wherein the locking device comprises: - an elongated member; - a protruding part from the elongated member, wherein the protruding part, comprises - a bottom part; and - a top part, wherein the top part comprises a pushing-surface and a contacting-surface, and wherein the elongated member is able to pivot on a pivot axis between a first position and a second position such that: - in the first position, the elongated member is positioned such that the bottom part is inside the slot, and such that the top part is inside the housing, whereby the contacting-surface and the pushing-surface are inside the lamp housing; - in the second position, the elongated member is positioned such that the bottom part is outside the slot, and such that the top part is partly inside the slot, whereby the contacting-surface is contacting a part of the outer surface and the pushing-surface is between the inside of the housing and the outer surface, whereby the lamp housing is able to be wedged in the installation-opening by the elongated member, - an elongated member; - a protruding part from the elongated member, wherein the protruding part, comprises - a bottom part; and - a top part, wherein the top part comprises a pushing-surface and a contacting-surface, and - a bottom part; and - a top part, wherein the top part comprises a pushing-surface and a contacting-surface, and - in the first position, the elongated member is positioned such that the bottom part is inside the slot, and such that the top part is inside the housing, whereby the contacting-surface and the pushing-surface are inside the lamp housing; - in the second position, the elongated member is positioned such that the bottom part is outside the slot, and such that the top part is partly inside the slot, whereby the contacting-surface is contacting a part of the outer surface and the pushing-surface is between the inside of the housing and the outer surface, whereby the lamp housing is able to be wedged in the installation-opening by the elongated member,