The CM-4100RE from Camden Door Controls is a spring return, N/O, momentary, red button with 'ExIT' engraved in white. Camden Door Controls 4100 Series of push switches are heavy duty pushbuttons, specially designed and manufactured to meet the stringent demands of exit controls. buttons are available in either green, red, or blue, 1 0.6" diameter. They are supplied with a 0.2" thick brushed aluminum plate in 1 0.7" or 2 0.7" widths. Optional duranodic finish (US 40) is also available.No set screws are required, due to the bayonet interlocking of the modular assembly. buttons are free spinning, for additional protection against vandalism.The switches are Ul/CSA approved, rated at 6A at 30V DC. The design of the Camden Push button is modular, so that the contact block switches can be stacked to control up to six distinct functions simultaneously. They can be configured for either spring return (momentary), push / pull (maintained), or push/turn to release (maintained) operation. Optional 1-60 second pneumatic timer. Pneumatic timer features 6A at 30V DC form Z (N/O and N/C) contacts.