Monster Hunter International
Tritium Night Sights
These otherwise normal iron sights have small dots which glow in the dark.
Under normal circumstances, tritium (try-tee-um, or tritt-ee-um) iron sights function as normal weapon sights. They show their value in low-light or no-light situations.
This type of iron sight consists of normal sights, which have been given tiny drill-holes. The holes are filled with a cylindrical glass vial about one millimeter in diameter. The glass vial is filled with a radioactive gas known as tritium. The rear of the vial is coated with a phosphorous compound. Tritium gas decays by beta negative emission. This means it emits an electron. Whenever an electron strikes the phosphorous compound, the compound becomes excited, and releases a light photon. The result of this setup is iron sights that glow lightly in the dark. The light is just bright enough for the shooter to see clearly, but not bright enough to reveal his / her position under most circumstances.
Tritium sights do not require batteries.
Tritium sights are strong for the first 2 or 3 years after their manufacture, but remain useful for their intended purpose for about 8, but could be longer or shorter, depending on manufacture methods.
Normal tritium iron sights can be easily attached to a gun which uses normal iron sights by a competent gunsmith with the correct tools.
Iron sights which are flip-up / fold-down accessories can be made as tritium iron sights with only marginal additional cost.
Tritium sights reduce the shot penalties normally associated with low-light circumstances by 3. They reduce the penalties associated with total darkness by 1.