The Strike Industries Aluminum Extended Magazine Plate for GLOCK(TM) G17 (9mm) / G22 (.40 cal) was designed to provide smoother magazine reloading through a slow drag / no snag design while maintaining maximum magazine capacity. Machined from 6061-T6 aluminum, this Extended Magazine Plate (EMP) adds plus 5 9mm or plus 4 .40 cal rounds to compatible OEM double stack GLOCK(TM) magazines. Following the success of our EMP systems for pistols, the form factor and unique geometric design gives a unified and aggressive aesthetic look to your GLOCK(TM) G17. Included is an aluminum plate which adds extra locking security. Give your GLOCK(TM) pistol the extra rounds it deserves with the Mfg: Strike Industries