slid in a downward direction until the shanks of the screws 3 a 3 b are firmly against the top slots of the keyholes 7 a 7 b the screws 3 a 3 b are then tightened the opening 6 in the mounting and alignment plate 5 allows the switch lever 1 to protrude through the opening 6 when the alignment plate 5 is affixed to the switch cover 2 the main housing unit 46 contains the operating electrical and mechanical parts of the invention the main housing unit 46 is mounted and aligned to the mounting alignment plate 5 by the use of the mounting alignment plate guide holes 8 a 8 b 8 c 8 d that are located at the four corners of the mounting alignment plate 5 and by the use of the corresponding four guide pins 9 a 9 b 9 c 9 d shown in fig2 of the back cover 42 shown in fig2 the four guide pins 9 a 9 b 9 c 9 d shown in fig2 are aligned with the guide holes 8 a 8 b 8 c 8 d and the main housing unit 46 is then pushed onto and into the alignment plate 5 until the mounting channels of the alignment plate 4 a 4 b and the corresponding mounting strips 16 a and 16 b shown in fig2 of the back cover 42 are engaged and interlocked the front cover 10 has a small access cover 11 which can be flipped open by the use of a hinge 12 at the top of the access cover 11 further there is an indicator light 13 protruding through the right top surface of the front cover 10 and.