There's been a flood of backup sight designs over the last couple years as some shooters who use holographic optics recognize the need for shorter-range options or an alternative if the power goes out on their primary.
Dubbed the Rapid Transition Sight, it was designed by SureFire's suppressor division head Barry Deuck to be a simple, elegant solution for shooters who use a magnified optic as their primary sight.
-Ultra-Durable: Machined from 7075 aluminum alloy bar stock, light weight and twice the strength of 6061 T6 aluminum
-½ MOA elevation and windage adjustments-Mil-Spec Hard Anodized finish
-Same height above bore as standard M4/M16A4 sights
-Ambidextrous: can be mounted for left or right hand shooters
-45 degree offset
-Low profile over picatinny rail only rising 2/10th of an inch so that it does not interfere with your primary optics
-Mounts directly to the top picatinny rail of your rifle
-No Special Tools Required: only uses a flat head screw and can easily be done in the field
-Compatible with military IR Laser/Illuminators, front sight designed to clear beam path
Looks like a simple solution for those who might have to make these transitions in a combat environment like Afghanistan where your Trijicon might work well for engaging ambushers or FOB attacks, but when the doors are being kicked, the 4x might be too much.