kwa kriss vector gbb submachine gun airsoft gun(Airsoft Gun) Gas operated recoil blow back Realistic construction & field stripping Fiber reinforced polymer upper & lower receiver Aluminum alloy inner frame Adjustable hop-up Closed Bolt, simulated KRISS System delayed-blowback Accessory rails Adjustable front and rear folding sights Folding stock Sling mount Vertical foregrip Semi-automatic, 2 round burst, and automatic select-fire