Normally during "up shifting" you must roll off of the throttle and pull in the clutch in order to engage the next higher gear. In racing (both drag and road race), split seconds count.
Rolling off the throttle, even slightly, slows your times and can be the difference between winning and losing. The Dynojet Quick Shifter (DQS) allows full throttle, clutch less shifting.
This is done by momentarily cutting the fuel and or ignition, which unloads the transmission. During this time, the rider can shift up to the next gear without rolling off the throttle or using the clutch.