All Isobrite models come with Swiss T100 tritium illumination, the world's brightest.
What is the difference between T25 and T100?
The T25 and T100 designations refer to the combined amount of tritium gas that is hermetically sealed in the tritium markers. T25 watches have up to 25 mCi (millicuries) of tritium gas whereas T100 means there is up to 100 mCi of tritium gas in the watch. T100 represents the latest technology in tritium watches and makes seeing the time in the dark much easier on the eyes.