Otis Lexan
These older fixtures produced by Otis are commonly called "Lexan" within the elevator community, though that is not their official name.
This video shows you how to wire an Otis Lexan elevator button, and it is very easy to do!
These buttons use the PSB type of bulb, so if you want to run this on a battery, you can pick up some 6PSB bulbs and use a 9 volt battery.