Always losing your keys? Turn off the lights and you'll instantly see them with the Neon Glowring key ring, and it doesn't even need batteries. That's because it works with a Gaseous Tritium Light Source (GTLS). Uh-oh. Isn't that radioactive? Yep, that's why it doesn't need batteries, and its glow will be visible for up to 20 feet for the next 10 years.
Funny, but you can't buy one of these in the UK because it's radioactive. But it's not that radioactive. Is it? Not sure we'd want to have one of these around. It'll cost you $17.34 to see if the thing burns a hole in your leg.