Shield Arm's steel mag catch is optimized to work with the Shield Arms S15 magazine. While it remains compatible with plastic OEM magazines, it can cause increased wear on plastic mags with prolonged use, and OEM mags may not drop free.
Armaspec, Glock 3 Pin Kit Set, For Gen 1-3, 1-Trigger Pin, 1-Locking Block Pin, 1-Ejector Housing Pin 3Rd Gen Full Length, 1-Extended Ejector Pin, Stainless Finish, Will Not Fit Glock Models 36