Sig Sauer ROMEO 4 Low Profile Red Dot 2 MOA Gun Scope (Romeo4A) Romeo4 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