Audiotex 15-500 vs First Alert SA76RS vs Honeywell TC89 contractors model sensitivity test.

Hey everyone here is another sensitivity test via smoke spray between my Audiotex 15-500 circa 1976, Honeywell TC49(B) contractors model from 1978 even though it has an earlier 1977 style cover which I also forgot to mention has a Kobishi CLB 27 horn instead of an Edwards horn which these usually had and last my First Alert SA76RS also from 1978 which was one of the first detectors in my collection when I started collecting in late 2017 early 2018. This time around the Audiotex sounded first and the Honeywell and First Alert started around the same time. The Honeywell was the last to stop sounding. And yes noisy but amazingly no jump scares this rime around and done without ear plugs!!!