Diamondhead Polymer (Flip-Up) Diamond FRONT Sight - with NiteBrite insert (Black) Advanced polymer/composite construction for strength, light weight & exceptional durability Nitebrite- photo luminescent inserts (the low-cost alternative to tritium) - can be charged by natural light or with a flashlight Spring-loaded sight flips up quickly with the push of a button, stays up securely and folds down flat Patented diamond-shaped upper housing for fast alignment with the polymer diamond rear sight Easy elevation adjustment (with no tools)