engaging the circuit contacts 12 14 16 18 20 and 22 although a number of circuit contacts 12 14 16 18 20 and 22 are shown more or less can be provided as needed depending upon the lighting system the slideable electrical receptacle 34 may be inserted at the top of the slot 6 see cap 78 fig8 which is removable the electrical receptacle 34 is generally t shaped in configuration and includes plugs insert holes 48 above the insert holes 48 is a lever 50 which permits the electrical receptacle 34 to be moved manually up and down in the slot 6 a plug 52 is provided with prongs 54 which engage the plug insert holes 48 the number of prongs 54 in the plug 52 will depend upon the number of circuits utilized and carried by the electrical receptacle 34 at the rear of the plug 52 is an electrical connector 56 carrying a series of contacts 58 as best seen in fig1 a and 1b the plug 52 at the top thereof includes a dovetail 60 wire leads or clips may be used in place of connector 56 a light receptacle support body 62 includes a slot 64 which receives the arm 66 of the bracket 28 the dovetail slot 68 receives the dovetail 60 of the plug 52 the light receptacle support body 62 receives the sleeve portion 70 of the light 72 the electrical connector 56 on the plug 52 connects with the electrical circuitry not shown of the light 72 fig5 shows a panel p with slots 6 for mounting various adjustable light display units f it is to be noted that the panel can have straight or curved walls fig6 shows a free standing display pole x with lights 72 which may carry.