aft of the lamp housing and spaced to provide passages between them for the free flow of air the radiation shield 230 is made in two c shaped parts long side edges of which overlap the corners of the parts are formed on a radius except through a length intermediate their ends slightly greater than the length of the heat sink where the corners are embossed outwardly to provide a debossed inside seat of each corner to receive corner fins of the heat sink the radiation shield and the heat sink 240 are mounted tightly together by rivets 235 which project through the overlapping edges of the radiation shield 230 the caging of the fins in the seats locates the heat sink accurately and precludes shifting of the heat sink the arrangement also limits the contact between the heat sink and the radiation shield to line contact the radiation shield 230 has an opening in it in which the heyco bushing 221 is seated as shown in fig1 the stem 217 of the yoke pin 215 thus projects into a space between the radiation shield 230 and the wall of the heat sink 240 in a space between successive fins mounted within the heat sink 240 is a reflector 250 the reflector 250 is made of semi specular material has an.