These are factory original, drop-free magazines for your Glock handgun. Glock magazines have a hardened steel insert encased in high tech polymer. This polymer coating protects the magazine and prevents deformation, even when dropped from a great height. Caliber: 9mm Capacity: 24 Rounds Not for sale to residents of California, Colorado, Connecticut, DC, Hawaii, Chicago and Cook County IL, Maryland, Massachusetts, New Jersey, and New York.