A lamp unit has a reflector (62) having a reflector surface (64) with an inverted U-shaped aperture (66) formed therein and extending through said reflector to an opposite surface (68). The inverted U-shaped aperture thereby has a bight (72) uppermost with a pair of channels (74, 76) depending therefrom. A light-shield has a cup-shaped member having an arm (52) projecting therefrom. The arm (52) has a distal end (50) formed to provide a pair of spring-loaded nibs (54, 56) for engaging and penetrating the channels (74, 76) of the inverted U-shaped aperture (66) and surrounding and grasping the bar (78) formed between the channels.