The Williams Gun Sight Adjustable Fiber Optic Rear Sight features a 1/4" WGOS (Williams Guide Open Sight) design with a green fiber optic insert for enhanced target acquisition and accuracy.Adjustable Fiber Optic Rifle Rear Sight1/4" WGOS mounting systemGreen fiber optic for excellent visibilityFully adjustable for windage and elevationDurable construction for hunting and target shootingIdeal for hunters and sport shooters seeking improved sight picture and faster target acquisition in various lighting conditions. The bright green fiber optic provides clear sight alignment for enhanced shooting performance.