Howdy. Recently I was at a mall with my folks looking around, and I saw an interesting find in a jewelry store. Like the title suggests, it was an unlabeled AS with a blue strobe. But the rest of the system had Spectralert Classic horn/strobes mixed with Spectralert Advanced remote strobes. My guess is it’s used as a security alarm, as there was a jewelry case under it.
Anyone ever see one before? And why would they use a Wheelock alarm when System Sensor also makes colored horn/strobes?
I am thinking that is for general alarm purposes.
Here is a http://www.cooperindustries.com/content/dam/public/safety/notification/Resources/Specification%20Sheets/Wheelock%20Colored%20Lens%20Strobes.pdf datasheet for them.
This is probably a security alarm.
Why a Wheelock instead of System Sensor for consistency?
Well, not the same company did the security alarm and they use wheelock, while the fire alarm is System Sensor.
So…
To build on what NewAgeServer said, even if it was done by the same company, that company could have picked that brand for a ton of reasons. Some of the most common are: price, availability, company preferences, etc.
Or a technician could have just picked a random general alarm for the job. (that how they do it for any type of fire alarm at my school; it makes replacing alarm interesting 
)