The Warne Maxima Horizontal 1 inch low PA Scope utilizes proprietary sintered steel technology featuring 4 screw ring caps, along with a square, permanently recoil key and clamp for positive engagement of ring to base, also offering easy installation and holding strength. The STANAG-4694 interface allows for a better return to zero and rigidity. The Warne Maxima fits both Picatinny and Weaver style bases