IMPORTANT NOTE: This product DOES NOT include tritium vials. Please refer to our Tritium Primer to learn more about tritium and where to purchase it. The TEC Isotope Atom is a coin style titanium fob designed to hold numerous glass tritium vials (not included), which will glow continuously for many years without the need to charge it from sunlight or UV light. This version of our Isotope Fobs has 6 individual bores to retain the tritium vials, which are visible from both sides of the housing. This offers maximum visibility of the tritium glow regardless of which side is facing up. The Atom can hold several combinations of tritium vial colors, allowing you to be as creative as you like with color and placement of the vials. It will accept up to six 3mm x 11mm vials, and they are extremely easy to change out so you can add more vials or switch up your color design. Once you install the tritium vials into the bores, the outer groove of the disc accepts an o-ring which holds the vials in place. If you ever want to change or add tritium vials, simply remove the o-ring from the groove, make your desired changes, then insert the o-ring back into the groove. It's that simple. Locate your bags in that pitch-black hotel room, find your keys in the dark, or simply have the most unique glowing necklace charm. Whether you use the Isotope Atom as a functional zipper pull or to simply identify your gear, there are a multitude of uses that will look absolutely amazing.  Isotope Atom Features: Designed to accept 6 tritium vials Each bore can hold one 3mm x 11mm vial Combine different colored tritium vials for a beautiful effect Grade 5 titanium housing Bead blasted, uniform matte finish Thru hole for jump ring (included) or ball chain (not included) What you get: (1) TEC Isotope Atom Fob Packaged with o-ring and jump ring (pre-installed) Jump ring size: 1.5mm [.06"] wide x 12.0mm [0.47"] outside diameter for attachment to other items Important Note: Product DOES NOT include tritium vials Specifications The TEC Isotope Atom is a metal housing suitable for mounting multiple glass tritium vials. Material: Ti-6Al-4V Titanium Finish: Bead Blasted Outside Diameter: 35.0 mm [1.378"] Width of Housing: 5.0 mm [0.197"] Jump Ring Hole Size: 3.18mm [0.125"] Jump Ring Size: 1.5mm [.06"] wide x 12.0mm [0.47"] outside diameter Total Assembled Weight (without tritium vials): 9.4 grams [0.33 oz] *Does not contain tritium vials Tritium Vials The TEC Isotope Fob Series are keychain fobs specifically designed to mount standard 3mm x 23mm and/or 3mm x 11mm self-luminous tritium vials. They do not include tritium vials, you must purchase them from another source typically outside the United States. Learn more about what tritium is and where to buy it by clicking here.