The SOS 12 is the latest Siren Operated Sensor that will open a gate for an emergency vehicle within 3 seconds of the sounding of a 'Yelp' siren.
The SOS12RM is a combo unit that saves you money when your are purchasing an SOS-12 and a Remote Microphone.
Used when ground and equipment noise interfere with the operation of the SOS-12.
This sensor is the latest update to the original SOS Sensor and comes with the larger 8"x10" sign.
These older models are no longer available to purchase but you can still get supporting documentation for them.