Push-pull switches are three position: off-on-on. First on position energizes one circuit. Second on position for energizing both circuits. Mounting stem is 1 1/4" long. Diameter is 3/8". Brass hex back-up nut and washer with chrome plated brass face nut and chrome plated plastic knob. Supplied with three 1/4" male blade terminals. Alternate part numbers: Sierra 8-MP39590, SIE_MP39590, SIE-MP39590, SIEMP39590, 47-MP39590