Ed Brown Performance Magazines for GLOCK 9mm pistols are manufactured just like the traditional magazines with a steel line and polymer outer body. Held to the same exacting standards as you have come to expect from all Ed Brown Performance Magazines. Offered in 9mm with a 15 round, 17 round, and the 31 round magazines, to work in the pre-Gen5 Model 17, 19, or the 31 round magazines can work in any 9mm GLOCK as well as AR9mm that accept GLOCK style magazines as well.