$59.00 on Amazon
A gas fluorescence keychain will provide advanced and highly innovative light, particularly when keys are thrown into a purse, backpack or bag. The lights come in seven different colors, with green being the brightest and blue being the softest.
The secret to illumination in these keychains is gaseous tritium, which in simple nuclear science is a form of hydrogen but with different atomic characteristics. The keychain tube is lined with a phosphorescent material. The tritium hits it and illuminates it.
Tritium is often used in glow in the dark watches or permanently illuminated exit signs. It's particularly useful for divers as they need to be aware of their down time and decompression time coming back up. Blue is primarily used by divers since it remains visible in the water longer and up to over 180 feet in depth.
No power source like a battery is needed for these keychains. They never need to be plugged into a charger. They're different than a keychain containing glow powder because they don't require exposure to light to charge and light up. They'll light up for years into the future.
With the gas fluorescence keychain, it isn't the light that's colored but instead, it's the casing around the light. The difference in brightness between the yellow light and a clear light is negligible though as no power source is needed for the light, the gas fluorescence keychain will be most appreciated at night when you've dropped your keys between or under your car seats.