Abstract: Electromagnetically operated contactor or relay employing contact modules which are removably mounted in either of two positions respectively providing normally open and normally closed contact conditions. One set of contact modules is mounted in a main frame and a second set is mounted in an upper frame which overlies the main frame and obscures the first set of contact modules. Transparent viewing members extend through apertures in the upper frame. Each transparent viewing member has a viewing surface exposed externally of the upper frame and an image transmitting surface adjacent to a contact module of the underlying first set. Each contact module has two light reflecting surface areas which are distinguishable from each other, one or the other being adjacent to the image transmitting surface of the associated transparent viewing member depending upon the position of the contact module.