case the coating material is preferably white and is polished to a measure but has a certain degree of surface roughness so that the light is reflective with some random diffusion the surface coating 28 is shown on the enlargement 18 which confronts the bulb 15 and it is extended along the full length of both the side walls 26 in addition it extends along the backing member 25 at the opposite end of the apparatus an enlargement 30 is also illustrated it is thicker than the enlargement 18 shown at the left but the two have a common width and common height the enlargement 30 is thicker to enclose the conductors and the socket 40 in particular the enlargement which fully surrounds the socket 40 has an internal chamber 42 which is provided for the first electrical contact 16 a similar chamber 44 is included in the socket 40 the pins 16 and 17 insert directly into a pair of aligned holes at 46 and 48 these guide the two pins into the chambers 42 and 44 the chambers 42 and 44 each receive coil springs bearing against suitable contact plates for pinching on or clamping against the pin contacts 16 and 17 that is electrical contact is assured whereby the wires 24 and 36 are inserted at the backside of the socket 40 while the pins 16 and 17 insert at the front side and contact is assured in operation of the two coil springs the coil springs bear against the pins 16 and 17 and the current conductors 24 and 36 to assure proper contact for illumination the enlargement has a similar slot and leaf spring to clamp on the spade the present structure thus comprises an.