Romeo 4M sights are parallax-free so point-of-aim is point-of-impact and the Red dot remains Parallel to the bore of your firearm, no matter what your viewing angle is relative to the optical axis of the sight
Unlimited eye-relief allows you to acquire the aiming point and the target regardless of the position of your eye behind the sight
Dual reticle option, on select models, toggle between 2 MOA Red dot or circle dot (2 MOA Red dot with 65 MOA circle)