Designed by Barry Dueck and available through SureFire, the Rapid Transition Sights are now available in three different configurations.
Based in the M16A2 rear and front sight pair, the RTS mount to a Picatinny rail. They present at a 45 degree angle so that you can roll off of your telescopic optic to use the RTS as a backup sight or for close in targets.
In addition to the original model, there is a version with tritium inserts as well as a fiber optic insert. The tritium version incorporates a larger dot at the front sight and two smaller tritium dots on rear sight for easy alignment in low-light conditions. The fiber optic model includes front sight in red, green, or yellow.
www.surefire.com/tactical-equipment/rapid-transition-sights