Agency Arms Glock 17/22 9mm +5 Rounds Pistol Magazine Extension OD Green 5. This base pad is specifically designed for the 17rd magazines. It is not compatible on reduced capacity magazines. Specifications for Agency Arms Glock 17/22 9mm +5 Rounds Pistol Magazine Extension: Manufacturer: Agency Arms Magazine Capacity: 5 Round Caliber: 9mm Luger Gun Make: Glock Gun Model: Glock 22 Glock 17 Features of Agency Arms Glock 17/22 9mm +5 Rounds Pistol Magazine Extension Sage Dynamics Engraving Dot Matrix Panel for Marking Chrome Silicon Alloy Spring Increases capacity by 5 rounds (9mm) 4 round (.40s&w & .357) Extended Ledge for One-Handed Manipulations Package Contents: Agency Arms Glock 17/22 9mm +5 Rounds Pistol Magazine Extension What firearm models does the manufacturer say Agency Arms Glock 17/22 9mm +5 Rounds Pistol Magazine Extension is compatible with? The manufacturer suggests that Agency Arms Glock 17/22 9mm +5 Rounds Pistol Magazine Extension is compatible with Glock 17 Glock 22Agency Arms AGEBP-G17-SAGE: Glock 17/22 9mm +5 Rounds Pistol Magazine Extension OD Green