OTIS AAA23500 AK27 has a mirrored concave stainless steel button and an outer ring that lights up green. LEDs are concealed in the switch and glow bright green when 24VDC is connected to terminals on the connector. Mounts in a 1.05" hole (no mounting nut available). Switch is momentary, N.O. (normally open), and closes when the button is pushed. Size of outer ring: 1.18" x 0.82" deep. Brand new – retails for $38.00.