The S15 magazine is a Patented, 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. Glock pistols and magazines are known for reliability - the S15 maintains that same Glock reliability, while giving you a 50% increase in magazine capacity in the same overall footprint. We accomplished this increased capacity with our patent-pending magazine geometry, allowing the rounds to stagger, thereby fitting more in the same amount of space. Specifications for Shield Arms S15 Gen 3 Glock 43X/48 15 Round w/ 2 Round Mag Extension Pistol Magazine: Manufacturer: Shield Arms Gun Make: Glock Gun Model: Glock 48, Glock 43X Caliber: 9mm Luger Magazine Capacity: 17 Round Features of Shield Arms S15 Gen 3 Glock 43X/48 15 Round w/ 2 Round Mag Extension Pistol Magazine: Unique easy access floor plate design to service or clean the magazine body without the need to remove the magazine extension from the magazine body. Index cuts on the extension body to increase grip when coming out of a magazine pouch. Machined from billet 6061 aluminum Type 2 anodized Adds 2 rounds to Shield Arms S15 Gen 3 Nitrocarb magazine  Comes with a 11 coil plus power spring Fits most aftermarket flared mag wells Lifetime warranty Package Contents: Shield Arms S15 Gen 3 Glock 43X/48 15 Round w/ 2 Round Mag Extension Pistol Magazine This product is compatible with the following gun models: Glock 43X, Glock 48