With a half-life of 12 years, the 3-Dot tritium system allows for fast target acquisition in low-light conditions Oversized chemical resistant fluorescent polymer front dot gives confidence in any environment Sights come in standard SIG SAUER sizes of #6 and #8 in square or round (U)notched rearsight Torture tested to 20,000 rounds, the steel housing provides for a tough, reliable sight that lasts as long as the firearm Fits P320, P938, P238, P229, P226, P220, P227, P225