With the G17 Gen5 MOS FS, GLOCK enhances the already near-perfect Gen5 model of "The original" with the addition of the Modular Optic System (MOS). The slide is precision machined to provide a mounting system for popular optic sights. With multiple adapter plates, you can quickly and easily mount miniature red dot sights to the rear of the Gen5 GLOCK slide, which has front serrations for easier and quicker manipulations. All of the Gen5 qualities are present in this standard-size pistol: The latest GLOCK nDLC surface finish on the major metal components, unmatched in hardness and rust resistance; the high traction Gen5 frame texture, quickly reversible magazine catch, ambidextrous slide stop lever, the GLOCK Modular Backstrap System (MBS) for individual operator adjustability, the universally-acclaimed GLOCK Safe Action System and high visibility orange magazine followers. Includes three 17-round magazines.