47 allows the light to pass therethrough but protects the leds 24 from exposure to the elements the cover 47 may have an anti reflective coating and can be flexed into place so the light will pass through the cover at close to right angles to minimize reflections the two columns 22 and 23 of leds are mounted on metal core boards with a dielectric layer aluminum and ceramic 48 and 49 by conventional techniques and methods the bi metal boards 48 and 49 are in turn mounted to the side surfaces 51 and 52 of the cross member 39 the interface between the boards 48 and 49 and the side surfaces 51 and 52 respectively need to be such that the heat transfer characteristics of the interface are maximized one approach is to use a double sided heat transfer thermal tape as the interface another approach is to use a heat curing epoxy as the interface still another approach would to be use a mechanical fastening means with a heat transfer compound being applied between the boards 48 and 49 and their respective side surfaces 51 and 52 it will be seen that the structure of the cross member 39 is such that the side surfaces 51 and 52 are angled at an angle u03b8 from the plane p as shown by the dashed lines the installed boards 48 and 49 and their attached led columns 22 and 23 are of course also angled in the same manner such that their projections are.