Simplex 4904-9175 and Wheelock MT-12/24-R All Tones Test

This is an interesting one for sure.
For this combo, I put a Simplex 4904-9175 110cd strobe on a 4905-9925 adapter plate, then paired that with a Wheelock MT-12/24-R multi-tone horn. The 4905-9925 and more common 4905-9921 are adapter plates you can use with a rectangular 4904 series strobe to make a retrofit plate. The difference between the 9921 and 9925 (seen here) is that the 9925 has holes on the edges to mount the plate to a 2975-9145 box, making it easy to replace a dead 2903. The 9921 does not have that feature, but also has more room to fit a device with a larger back. The horn is your average 8 tone Wheelock MT, only this one was manufactured for Simplex with a part ID of 4901-9821. I'd assume Simplex would use this as a multi-tone and/or weatherproof device before the TrueAlert and TrueAlert ES multi-tone and outdoor models.
Enjoy!