The AR Low Profile Flip-Up signts are crafted of black anodized aircraft grade aluminum and feature a ball bearing pivot detent that automatically locks into position when raised. Single plane front sight for use with standard height AR-15 rear sights. Locks positively in the up position.Features:Ball bearing pivot detentAutomatically locks into position when raisedFlip-up posi-lock design to guarantee zeroQuick detachable with adjustable A2 square postUses standard A2 sight postSame plane hand guard/upper receiver height