this is my second model, so be kind :)

this model is intended to hold a smoke detector ( e.g. https://www.amazon.com.au/UanTii-Smoke-Detector-Wireless-Security/dp/B0DF63XQYD )

i wanted to mount a smoke detector on the ceiling, but didn't want to drill holes or use any glue, so having this cage/mount to attach to the preexisting light fixture seemed like a good idea

the photo includes a smoke detector, inside this model, hanging from the fluorescent light fixture mount ( https://www.printables.com/model/1167839-fluorescent-light-fixture-attachment ), installed on a light fixture