sentences:  In addition to the original Flat Black finish, optional factory Cerakote coatings now come in Olive Drab (green), Flat Dark Earth (tan), Alpine (white), or Combat Gray.The Vector SMG variant is only available for military and law enforcement use.It features a 5.5-inch barrel (with an option of a 6.5-inch barrel on the Gen II version), a folding stock, flip-up Midwest Industries back-up iron sights (BUIS) (MagPul MBUS on Gen II weapons), a full-length Picatinny rail for mounting various optics/scopes, and either two mode fire selector (single and full-auto) or a three mode fire selector (single, two-round burst and full-auto).