The KRISS Vector series are a family of submachine guns developed by KRISS USA, formerly Transformational Defense Industries (TDI). They utilize asymmetrical recoil and in-line design to reduce recoil and muzzle climb. The Vector's barrel is in line with the shooter's shoulder as in the M16 rifle and German FG42, but also in line with the shooter's hand as with many target pistols. Combined, these factors are claimed to reduce felt recoil and muzzle climb by eliminating the distance between the shooter's hand and the bore axis. It comes with backup iron sights and a rail for mounting optics.