1. A PUSH-PULL KEY HAVING A SNAP-ACTION EFFECT COMPRISING A CONTAINER HAVING WALLS THE INNER FACES OF WHICH FORM A CLOSED BODY, REED CONTACTS HAVING PAIRS OF CONTACT POINTS ENCLOSED AT ONE END OF SAID CONTAINER AND CONNECTING TO TERMINATE OUTSIDE SAID CONTAINER, A MOVABLE ARMATURE IN SAID CONTAINER, SAID MOVABLE ARMATURE BEING SUBSTANTIALLY SPHERICAL IN FORM, LARGE ENOUGH TO BRIDGE PAIRS OF CONTACT POINTS AND HAVING A DIAMETER SUBSTANTIALLY LESS THAN THE SPACES BETWEEN THE INNER FACES OF THE CLOSED BODY, AND AN ANNULAR PERMANENT MAGNET OF SUBSTANTIALLY CYLINDRICAL EXTERNAL FORM WITH AN INTERNAL BORE FORMING AN INNER OPENING OF ELONGATED CROSS SECTION AT RIGHT ANGLES TO A LONG AXIS THROUGH ITS OWN CENTER, SAID PERMANENT MAGNET BEING LINKED MAGNETICALLY TO SAID MOVABLE ARMATURE SO THAT MOTION OF SAID PERMANENT MAGNET WILL CAUSE SAID MOVABLE ARMATURE TO MOVE QUICKLY ALONG AND IN CONTACT WITH A SELECTED PORTION OF THE INNER FACES OF THE CLOSED BODY OF THE CONTAINER TO MAKE AND BREAK CIRCUITS BETWEEN THE CONTACT POINTS AT SAID ONE END OF THE CONTAINER AND TO PROVIDE A SNAPPING ACTION RELATIVE TO THE CONTACT POINTS.