Tritium Illumination

Tell the time. All the time.

Often overlooked but always greatly valued, the ability to tell the time with ease in the dark is the reason why each and every Nite watch is fitted with tritium illumination – widely regarded as the world’s best and most reliable form of illumination.

Tritium illumination is a completely safe and reliable form of illumination – the electron emitted by Tritium is so low in energy that it is unable to penetrate the human skin.

The Tritium illumination used in all Nite watches is supplied by mb-microtec of Switzerland – the original founders and market leaders of the technology.

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

Tritium illumination will provide a constant glow throughout the night unlike traditional illumination such as Superluminova which will fade in a number of hours.

Tritium comes in a number of different colour variants. We offer watches with green, blue and orange illumination with green appearing the brightest to the human eye, followed by blue and then orange.

Tritium illumination is completely self-powered and doesn’t require sunlight or any other form of external power to operate.


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 times brighter 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.


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.

T25 vs T100

Which is better and what's the difference?

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.

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