System Sensor MASS Year?

Does anyone know when the System Sensor MASS began production? Also, are there any other differences between first- and second-generation MASSes other than the strobe?

Any help would greatly be appreciated.

The oldest one I’ve seen was from 1989. Here is the patent for the strobe, filed in 1987.

I think the sounders have always been the same.

Thank you. Do you know when they switched from first generation to second generation? :mrgreen:

I would guess '92 or '93. Most brands had introduced clear strobes by then.