Shield Arms S15ME5INSG3BLK S15 Magazine Gen 3 15rd w/ +5rd Mag Extension (20rd Total) For Glock 43X/48 Black Nitride SteelThe S15 magazine is a patent pending, flush fitting 15 round magazine for the Glock 43X and Glock 48. The S15 is a steel magazine, and is the same length as the OEM Glock 10 round magazine, but holds an additional 5 rounds. What changed with the gen 3 magazine? We made the following improvements: US based manufacturer. Modular tooling. Raised ribs on the back of the magazine allows these to fully match the OEM magazine position in the mag well, which