Armourlite Tritium Vials Key Ring Safety Markers 4 Pack Green/Blue/Orange. No external power source or charging-by-light is necessary to maintain the glow. The glow is completely self-powered. These handy tritium glow Fob markers can be used to easily find important items or objects in the dark. Furthermore these markers are great for marking paths and locations. With the convenient stainless steel split key ring you can attach the markers to keys zipper pulls flashlights knives weapons eyeglasses (requires O-rings) personal protection devices camping lighters and more As an added bonus each marker features a glass breaker on the end making it ideal for safety applications. Specifications for Armourlite Tritium Vials Key Ring Safety Markers: Manufacturer: Armourlite Fabric/Material: Tritium Features of Armourlite Tritium Vials Key Ring Safety Markers Swiss tritium illumination Features a glass breaker on the end Package Contents: Armourlite Tritium Vials Key Ring Safety Markers Armourlite KeyRingGreenBlueOrange: Tritium Vials Key Ring Safety Markers 4 Pack Green/Blue/Orange