A Glock in the MOS version is a pistol with the Optics Ready feature - i.e. a place milled on the slide for the installation of electro-optical sights - usually mini collimators in the TrijiconRMR, Docter/Noblex style, Leupold Delta Point, Vortex Venom and many others.

The latest G43X and G48 models, which in themselves are relatively new products in the company's offer (to be more precise, the company numbers the models in the order in which they are created, i.e. Glock 19 was created later than Glock 17, but earlier than Glock 22), received MOS slides and already a bit earlier accessory rails for mounting tactical flashlights.

Let us remind you that these are models from the so-called Slimline Glock range, i.e. they are built using a frame with a narrowed grip and are fed from single-stack magazines. Both models include all the improvements from the Glock Gen 5, including the nDLC slide and barrel coating, the GMB (Glock Marksman Barrel) barrel and a magazine release that can be installed on the left or right side of the weapon.

Source: thefirearmblog.com, soldiersystems.net, officer.com, concealedcarry.com