Tritium Illumination

Tell the time all the time

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.

Key Features

  • 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 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.

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

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.


Very good quality and nice looking watch. Easily the best night time illumination I’ve ever come across in a watch. Given the 10 year battery life, this represents excellent value for money.

Philip Studd 23/9/19

The night time illumination is amazing, it seems that the darker it is, the brighter it gets. I'm all, I'm extremely happy with my purchase.

Keith Taylor 30/7/19

This is an excellent watch, very bright in total darkness, very robust, I'm sure this will do the test of time. Being an ex-commercial diver, this would make a brilliant working watch in and out of the chamber. Well worth the money, you would not be disappointed buying one of these watches. Once you put it on your wrist you will rarely take it off, only when you have to. Brilliant bit of kit.

Steve 6/10/19

This watch is worth the money. The markings glow bright at night. I have had several tritium watches in the past and this by far is the best. It's a very classic and classy style watch. You can wear it for any occasion.

Steven Kraus 8/10/19

Very happy with my watch, very bright at night, I can read the time without my glasses on.

Ian Woodcock 26/9/19

Now you know all about Tritium illumination

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