Designed to accept and function properly with 10mm Glock and SGM magazines, the Mk10 lower receiver assembly is built to the same fit and finish expected of any CMMG product. Featuring an integrated trigger guard, last round bolt hold open, as well as an oversized magazine release and flared magwell makes for quick and easy mag changes. The Mk10 lower comes ready to accept any AR-15 mil-spec Lower Parts Kit or Drop-In Trigger of your choice.Multiple Cerakote finish options standard.All CMMG products come with their Lifetime Quality Guarantee.**Mk10 Lowers are designed to work with CMMG Mk10 Uppers only**