The other night our fire alarm went off in the early hours of the morning. I always take my Fenix PD32UE out of its holster and leave it on my nightstand so I have it at the ready, and it was handy to grab it and immediately look around for smoke. I didn't see any, and the alarm actually turned off after just a few loud alarm sounds. About 10 seconds later it came on again once, but it has been quiet for the last couple nights afterward. I will vacuum and blow them out this weekend since I heard that sometimes small critters can crawl inside and trigger the alarms.