Here´s the official product review from Airsoftology on the Kriss Vector AEG.
Developed by world-renowned firearm developer KRISS Arms, the Krytac Kriss Vector SMG AEG Airsoft Gun was engineered as an accurate training platform. While this gun doesn’t use the innovative KRISS Super V System featured in the original, which redirects the bolt-off axis into a recess cavity behind the magazine well, it is designed to mimic its feel. This provides the shooter with superior control and quick follow-up shots, making it a popular choice for tournament-level play. The black Krytac Kriss Vector is made with high-quality materials for durability and strength, including a lightweight yet high-impact polymer receiver and folding stock plus MIL-STD 1913 Picatinny rails along the bottom of the handguard and across the full length of the upper receiver. The insides of this next-level AEG are pretty impressive, too, with an 8-millimeter gearbox that lets you plug in the battery and go. A quick-change spring system and an integrated FET system make this a popular AEG.