Alloy bases are made with strong cold drawn 12L14 steel and locked in place with high tensile strength Torx-style screws. A recommended upgrade for aluminum mounts that come standard on many firearms. Stainless recoil lug fits into the cross slot to handle magnum recoil and ensure precise return-to-zero performance on the quick detachable rings. Solid construction - not relived or hollowed out down the center. Made to work with Maxima and all Weaver-style rings.