The extension are a great addition to my Glock 17, 19, 22, 23, 26, 27 and 34 magazines. To have 2 additional rounds in your magazine can pay off in the heat of a battle.
Haven’t had the opportunity to go to the shooting range to test the Glock Plus Magazine Extension yet. But it was easy to install on the Glock magazine and no problem to report.
Nice having a G23 back up mags with 15 rounds. Had to work the spring inserts (also required) around the spring - that's why I held back a star - but it's good to go. Got same for my G26 - very happy.