Shield Arms Magazine, 9MM, 9 Rounds, Fits Glock 43, Powercron Finish, Black, Includes Steel Magazine Release Z9-STARTER-KIT Glock pistols and magazines are known for reliability - the Z9 maintains that same Glock reliability" while giving you a 50 percent increase in magazine capacity in the same overall footprint. Shield Arms accomplished this increased capacity with their patent-pending magazine geometry" allowing the rounds to stagger" thereby fitting more in the same amount of space.