XS Sight Systems MB-4000R-1 Shotrail, Ghost Ring, Standard Dot White - Mossberg 500, 590, 930 White on black front post that is perfect for all light conditions The White stripe draws focus to the front sight for fast target Reference Large ghost-ring affords great field of view for fast target acquisition Ghost-ring rear sight is fully adjustable for windage and elevation Sets include .230" and .191" I.D. Apertures