WE is proud to announce the new Modular Optic System (M.O.S) on our G Series Gen 3, 4 and 5 Gas Blowback Pistols.
The MOS system allows users to install pistol optics while keeping the iron sights as a Co-witness option, giving the users a choice of mounting a pistol optic without having to remove the rear sight and install a mounting plate. The mounting plates are designed to allow the mounting or various mainstream pistol optic systems.

It uses WE G17 MOS magazines!