Tritium Illumination





Being able to tell the time with ease in the dark is often overlooked in the process of buying a watch.

This ability however, of always being able to tell the time no matter what the conditions, is always highly valued in the day to day life of a watch.

This is the reason therefore why each and every Nite watch is fitted with Tritium illumination - the very best form of watch illumination available.


  illuminating watch over fire Nite  


Completely self-powered and providing a constant glow throughout the night, Tritium illumination technology has been trusted for decades by the emergency services, mountaineers, deep-sea divers and military personnel due to its unwavering reliability and performance in mission critical situations.

  Blue tritium watch in water



Tritium, also known as super heavy hydrogen, was first discovered by Ernest Rutherford, ML Oliphant and Paul Harteckin in 1934.

Tritium emits electrons through beta decay and when these electrons interact with a phosphorous material, a fluorescent light is created that can last up to 20 years. When this Tritium powered illumination is sealed inside a glass tube, it is known as a GTLS (Gaseous Tritium Light Source) which is up to 100 timesbrighter over a long period than any comparable technology. To produce a GTLS vial, glass is lined with phosphorescent material, then filled and pressurised by a machine with gaseous tritium and sliced into segments by a laser beam to be sealed hermetically. Inside the vial, the electrons emitted by the tritium gas excites the phosphor to give off the cold continuous light. GTLS can be created in different colours, generally green is perceived by the human eye as the brightest colour. Based on green (100%), the brightest output of the other colours is as follows; ice blue 60%, white 60%, orange 40%. Blue GTLS, is often used in diving watches as it remains visible at up to 60m/187 feet in depth – longer or deeper than any other colour. If you have any concerns about the safety of GTLS technology, the electron emitted by tritium is so low in energy that it is unable to penetrate the human skin. It has also been shown that consuming 1 banana every other day causes the same dose as breaking a GTLS equipped watch (1GBq of activity) and absorbing 100% of its tritium content (mb-mictrotec). Further information on the safety of Tritium illumination can be found here:



T25 VS T100

We offer both T25 and T100 rated Tritium watches. The T rating refers to the total watch radiation content which is measured in millicuries.

All watches with a T25 rating contain up to 25mCi of radiation content and similarly, watches with a T100 rating contain above 25mCi and up to 100mCi. Whilst there are differences between the amount of mCi in the T25 and T100 models, the idea of “which is better” is simply a choice of preference and taste.


Tritium watch T25 v T100 GTLS  

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