Our Precision-built steel bases are machined to tight tolerances for a custom fit. A square-cut notch mates to the sturdy cross bolt in every Weaver Top Mount Ring. Custom-hardened fastening screws included. Grand Slam Steel - Built to pair with Weaver's Grand Slam Steel rings for an ultimate solid steel-to-steel mount. Rock-Solid Construction: Precision-engineered from solid steel to provide exceptional strength and dependability. Legendary Cross-Lock Design: Weaver's iconic design ensures your scope stays locked in place, even under heavy recoil. Maximum Durability: Equipped with Torx screws for enhanced reliability and resistance to wear. Proudly Made in the USA: Manufactured to exacting tolerances for unparalleled quality and reliability. Weaver Recommended Torque Specs 6-48 Screws: 15 in lbs 8-40 Screws: 18 in lbs Instruction Manual