UTG® Low Profile Flip-up Rear Sight with Dual Aiming ApertureUTG New Gen Super Slim Flip up Rear Sight for the AR Platform and Other Long Gun Applications Equipped with Picatinny Rail Precision Machined from Aircraft Grade Aluminum with Black Anodize Spring Loaded Posi Lock Design with Side Plunger Release for Positive Flipping Folding; Compress Plunger to Unlock and Fold Down When Not in Use Robust Posi lock Plunger Coupled with Spring Activated Ball Bearing Guarantees Zero Retention Complete with Dual Aiming