The KRISS Vector[8] series is a family of weapons based upon the parent submachine gun design developed by KRISS USA. They use an unconventional delayed blowback system combined with in-line to reduce perceived recoil and muzzle climb. The Vector's action, the so-called KRISS Super V System (KSVS), is an articulated mechanism which allows the bolt and an inertia block to move downward into a recess behind the magazine well.[9][not in citation given] The theory is that at the end of this travel, energy is transmitted downward rather than rearward. On return, however that downward force is negated by upward force. The Vector family of weapons is the first to use this action. It is the main SMG of the Task Force 141.