The Lantac M-SPEC Lower Parts Kit (LPK) for AR-15 style rifles combines Lantacs renowned engineering with precise heat-treated components and finishes designed to meet up-to-date military specifications, delivering reliability and smooth operation for builds and upgrades alike. This comprehensive kit includes every essential piece to complete your lower from takedown and pivot pins to detents, springs, and a robust ambidextrous safety selector, along with the safety detent and its spring, buffer retainer and spring, bolt catch with its plunger and spring plus roll pin, the bolt catch set screw (6-32 compatible with Lantac Aero and other lowers) with a 1/16th Allen key head, mag catch assembly with its spring and button, and all the associated springs and pins needed for a secure, repeatable cycling action. Engineered and manufactured in the USA, the M-SPEC LPK emphasizes durability, consistent fit across compatible lowers, and a seamless installation experience for rifle builds, replacements, or upgrades. With Lantacs lifetime warranty backing, shooters can trust a reliable foundation for precision, performance, and long-term service in rifle parts and build kits.