Fine Personal Accessories For Practical Obsessions

TEC-S311M Isotope Mini Fob


Bead Blasted Stainless Steel
Black Diamond Carbon

Product Details

The versatile TEC-S311M Isotope Mini Fob is designed around the use of a glass tritium vial (not included), which will glow continuously for many years without need to charge it from sunlight or UV light. Three slots on each side of the housing allow for maximum tritium visibility, while still offering superior protection for the glass vial. Very similar to the TEC-S323 and TEC-S360 fobs, the shorter profile of the Mini Fob adds a subtle touch of luminous style to your keychain.

The Isotope Mini Fob is an economical way to add a functional glow to anything you attach it to. You can also change out the vial anytime you like for different glow colors. Use different colors to identify different sets of keys! 

Complete your EDC collection with the small, functional and stylish TEC-S311M Isotope Mini Fob, which provides just the right amount of light for locating items in the dark. Perfect for attaching it to your keychain, camping gear, zipper pulls on gear bags or jackets, or try it on the pull chain on your ceiling fan. Where will you clip yours?

TEC-S311M Isotope Mini Fob Features:

  • Custom designed to hold a standard 3mm x 11mm tritium vial
  • Stainless steel housing
  • Bead blasted, uniform matte finish
  • Available in your choice of stainless steel finish or our exclusive Black Diamond Finish (see "Specifications" tab for details)
  • Smaller size than our other Isotope fobs

What you get:

  • (1) TEC-S311M Isotope Mini Fob
  • (1) 11.1 mm [7/16"] diameter split ring for attachment to other items
  • Packaged with 3 rubber plugs for tritium vial containment (1 required plus 2 spares)
  • Important Note: Product DOES NOT include tritium vial

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The TEC-S311M Isotope Fob is a metal housing suitable for mounting a 3mm x 11mm glass tritium vial. It is bead blasted to a uniform matte finish, or also available in our exclusive Black Diamond Finish.

  • Material: Stainless Steel
  • Finish: Bead Blasted
  • Outside Diameter: 5.0 mm [0.197"]
  • Overall Length: 20.5 mm [0.81"]
  • Split Ring Hole Size: 3.0mm [0.118"]
  • Total Assembled Weight (without tritium vial): 2.0 grams [.07 oz]
  • Total Assembled Weight (with tritium vial): 2.1 grams [.075 oz]


Black Diamond Finish

TEC’s Black Diamond Finish is a proprietary, nano-composite microlayer, uniquely replicating diamond’s low friction, high hardness and superb corrosion resistance. Genuine TEC products with Black Diamond Finish provide an extremely durable, near-black coating that offers exceptional wear resistance – Fine Personal Accessories for Practical Obsessions.


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.

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