Does anyone know about power failure alert/alarms?

I need a power failure alert; I’ve seen lights like this but since it says it comes on automatically when the power goes off, I’m guessing it probably turns off automatically when power comes back on. I need something that must be manually reset, so I will know if the power has been off at all, however briefly. We are on the end of a line, and we frequently get ‘hiccups’ where the power is interrupted for just a few seconds. But my husband’s shop has a propane heater system that shuts off if the power goes out. Then it must be manually reset. When he’s away, I have no reason to go in there, so I don’t notice if his heat is off, and he has an alarm that I would just as soon not have to mess with every day, just going in to check that the heat is on. Does anybody know if there is some kind of power failure alert, whether it’s a light or sound type doesn’t really matter, that doesn’t stop the alert once it has power again?