This response trigger is a drop-in kit for the US Army Project Salvo markers. The response trigger kit increases your trigger speed by resetting the trigger and sear with excess gas during firing. This gas is used to operate a cylinder behind the trigger to do the resetting. The pressure of your finger on the trigger pulls it back to fire the next shot. The speed is determined by the amount of flow through the knurled adjuster on the side. The upper limit on the rate of fire is set by this adjuster.