New for 2016, Glock introduced the MOS series of Glock pistols. MOS, which stands for Modular Optical System, is in simplest terms a modified slide with a set of 4 mounting plates to allow the installation of micro red dot sights like the Docter, EOTech, Leupold Delta Point, Trijicon RMR and other popular models.
This is an outstanding offering as factory Glock sights aren’t much to get excited about, and being able to mount a micro red dot sight on your Glock without having to machine down the slide is where it’s at for me.
THE MOS configuration is available for the following models
9mm: G17 Gen 4, G19 Gen 4 and G34 Gen 4
.40 S&W: G35 Gen 4
.45 ACP: G41 Gen4
10 MM: G40 Gen 4