GLK 19 GEN4 9MM PST 15 FS MOS. THIS IS THE MODEL YOU CAN MOUNT AN OPTIC, AS IT ALREADY HAS THE FACTORY MILLED SLIDE AND INCLUDES FOUR DIFFERENT MOUNTING PLATES TO ACCOMMODATE MOST PISTOL OPTICS! PISTOL COMES BRAND NEW IN THE CASE WITH THREE 15 ROUND GLOCK MAGAZINES, MAG LOADER, FOUR INTERCHANGEABLE GRIP BACKSTRAPS, CLEANING ROD AND BRUSH, AND ALL DOCS AND TEST FIRE SHELL.