The CMMG MK9 bolt catch is specifically engineered to seamlessly integrate with the CMMG MK9 dedicated 9mm lower receiver. This precision crafted component features an elongated Magazine tine, meticulously designed to accommodate the unique dimensions of the MK9's smaller Magazine well. This ensures reliable and consistent performance, enhancing your shooting experience with the MK9 platform. Please note that this bolt catch is optimized exclusively for the CMMG MK9 lower and may not be compatible with other dedicated 9mm lower receivers or Magazine block configurations. For those seeking a tailored fit and superior functionality within the MK9 system, this bolt catch is an essential upgrade.