The Tritium Keychain is a reliable source of low-intensity light that does not require electrical energy, or need to be "charged" by sunlight.
Mr.Sci’s Tritium Keychain uses the same technology that is found in professional applications, such as for diving purposes. As it will glow for up to 12 years without any assistance, it provides the user with a convenient source of light whenever needed. The light within a twisted spiral helix shape that's made from stainless steel, which protects the glass tube from impacts.
The Tritium Keychain comes in a variety of different colors, including green and blue, so that you can attach it on your backpack for easy identification in the dark.