The Tyrant Designs Glock Full-Size Mag Extensions - +5 9mm/+4 .40 Cal for Glock 17/22/34/35/19X/45 are easy to install! The retention plunger technology allows the extended base pad to easily slide onto the bottom of your magazine. These USA-made magazine extensions are CNC machined from aerospace-grade aluminum which keeps them strong and gives them enough weight for your base pad to drop free and fast.