18.5 KS-K is based on the Saiga-12‑ sporting and hunting shotgun and designed for use by law enforcement personnel.

It is a semi-automatic gas-operated smoothbore shotgun that provides high firepower at short ranges.

It is capable of using a wide variety of standard 12-gauge cartridges with 70- or 76-mm cases with buckshot, slug or birdshot, as well as special rounds.

The carbine features a side-folding polymer buttstock with a rubber recoil pad, polymer pistol grip and handguard.

It is equipped with a Picatinny rail on the dust cover and open iron sights.

The shotgun is fed from detachable 4- or 8-round box magazines.