sentences:  Reflector sights have unlimited eye relief, meaning that the user may place his eye at any distance from the sight and the reticle will remain visible.This allows flexibility in mounting and shooting position.The CompM4 uses Aimpoint's "parallax-free" optical correction system, meaning there is minimal induced optical error that would shift the point of aim "relative to the sight's optical axis" as the user's eye moves off-center in relation to the sight.