Abstract: A vertical array of closely spaced hairpin type contactors are mounted in horizontal channels in a vertical array to contact the closely spaced edge terminals of a vertically mounted circuit board. The hairpin contactors are moved within the channel toward and away from the circuit board by a pivoting toggle which is manually operated by moving a toggle lever back and forth horizontally. Camming surfaces along the hairpin contactors cooperate with camming surfaces along the channel walls (or camming surfaces on the circuit board) to spread and close the hairpin contactor, causing the hairpin contactor to break and make contact with the edge terminals. These camming surfaces plus detents on the toggle mechanism retain the hairpin contactor in defined ON or OFF positions relative to the circuit board.