The Marble Arms 31-MR Fiber Optic Front Sight features a bright orange fiber optic glow insert in durable steel construction with .312" diameter for enhanced target acquisition.Marble Arms 31-MR Fiber Optic Front Sight.312" diameter steel constructionOrange fiber optic glow insert for improved visibilityDurable steel housing for long-lasting performanceDesigned for rifle applicationsPerfect for hunters and shooters who need reliable bright sight alignment in various lighting conditions with the enhanced visibility of fiber optic technology.