Those Nuk Alerts are great. They last for years and you can send them in to have their battery replaced. One down side: When they move from a cold environment to a warm environment they chirp every 30 seconds or so until they’re stabilized. It’s a feature, not a bug. You can test to see if it’s working by sticking it in a freezer for a few minutes and then pulling it out. But it can be annoying and gives itself away to others if, like me, it’s part of your edc pack.
