UTG Tactical Flip-up Front Sight Quick Detachable Front Sight with Adjustable A2 Square Post Assembly to Fit All Picatinny/Weaver-style Rails Equipped with Locking RetentionThumb Nut Clever and Robust Flip-up Posi-lock Design to Guarantee Zero in the Most Extreme Combat Conditions Precision Elevation Adjustments to Enhance Shooting Accuracy