http://royalmarines.mine.nu/susat/susat.php
My AFCO says you may get asked about it in the PRMC interview. I can't imagine many people turning up for PRMC knowing about this....but it all helps hey....
I read this which unless you eat your scope then....well read it yourself
The knob on the right side is the Tritium brightness adjustment. The Tritium gas inside the tube glows illuminate the pointer (crosshairs) during low light condition.
Tritium Warning
Tritium is an isotope of hydrogen which has one proton and two neutrons . It emits beta particles only and has a half-life of 12.3 years. The maximum beta energy is 18 keV, and the mean beta energy is 6 keV. A beta particle with energy of less than 70 keV will not penetrate the dead outer layer of the skin. Therefore, tritium is not an external radiation hazard , but when taken into the body it becomes an internal hazard.

