The Warne Maxima Fixed Ring Series fit Weaver style cross slot bases and incorporate a Warne square stainless steel recoil control key in both the front and rear rings. This ensures a ?no slip? positive recoil surface across the entire slot of the base and is capable of withstanding the heaviest of recoil. Protects against swaging or peening of the bases when used on softer or less durable materialsSubstantially wider for additional clamping surface around the scope to hold the optic firmly in placeDesigned to fit Warne bases as well as all Weaver cross slot and Mil-Spec Picatinny style bases and rails