That one horn/strobe is mounted really high!
Wonder if the EHSes are replacements for some of the original 890-series NAs.
Those are actually also Edwards believe it or not: model numbers seem to vary when it comes to ones with that design but the ones I know of are the 6250B, the 6250C, & the 6264B (I also own a model that consists of a “P-847570-1044” head & a “P-847674-0123” base (yes those are the actual model numbers from what I can tell).
As SlyFox said, interesting way of mounting that annunciator.
The fact that the one TrueAlert isn’t mounted in line with the pull station below it really irks me.
I do believe that’s the very first system I’ve seen with CO detection capability! (& System Sensor’s CO detectors for that matter)