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 detent Automatically locks into position when raised Flip-up posi-lock design to guarantee zero Quick detachable with adjustable A2 square post Uses standard A2 sight post Same plane hand guard/upper receiver height