Night Fision's patented injection molded sleeve design holds their tritium vials securely in place using ballistic materials. Night Fision night sights carry more tritium than the average night sight on the market and a domed lens engineered to create the a crisp, defined glow. Brightest Tritium Night Sights on the market CNC Machined out of high quality steel Black Nitride coating used to improve wear and corrosion resistance Domed lens collimates tritium rays for a sharper sight picture