I was at my local SUNY college for Drivers Ed, and found this strobe mounted in the restroom. I didn’t know they had that option.
You can do that with pretty much any strobe that doesn’t stick out in the back. It’s just a 2-gang strobe mounted to a backplate.
Looks like the standard version of the strobe mounted on a combination adaptor plate. If turned 90 degrees, the holes you see next to the strobe on the plate can be used to mount 2-gang devices.
I believe Federal Signal manufactures a version of these plates for use with VALS series strobes.