Tritium Keychains glow for 10 years without batteries. This is because Tritium is actually radioactive.
I know. The idea of buying a keychain that you put in your pocket, next to your nuts that has the potential to break and leak radioactive liquid doesn’t sound so appealing. But I like to think you’ll probably just end up with super powers, or at the very least a third nut. And knowing that this is made in China pretty much instantly guarantees you a third nut.
So it seems like a win win situation. Three nuts, and a glowing keychain.