The CMMG 9AR 9MM Conversion Magazine is designed to work with Mk4/AR15 lower receivers paired with a CMMG 9mm Radial Delayed Blowback upper. This Gen II magazine features a 10-round capacity and maintains exterior dimensions that closely match those of standard 5.56 AR15 magazines, allowing for cross-compatibility with existing mag pouches and carriers.Key FeaturesCapacity: Holds up to 10 rounds of 9mm ammunition.Compatibility: Designed for use with Mk4/AR15 lower receivers and CMMG 9mm Radial Delayed Blowback uppers.Dimensions: Length measures 8.7500 inches, closely matching 5.56 AR15 magazine dimensions.