A Quickshifter is an electronic device used by virtually every high performance rider that attaches to your motorcycle and allows for clutchless upshifting.
Normally on a motorcycle you roll off the throttle, pull in the clutch, move the shift lever to the next gear; then release the clutch while reapplying throttle. This is how shifting has been done for 100+ years on motorcycles. All of this takes time, and also has the very negative effect of causing the motorcycle to change chassis attitude as the weight of the machine shifts back and forth during the shift.
A well designed Quickshifter allows the rider to stay on the throttle and without engaging the clutch, execute a virtually instant and incredibly smooth upshift to the next gear. The Annitori QS PRO does this electronically by momentarily releasing the torque on the gearbox while the rider is moving the shift lever, thus allowing the gear to be changed very quickly, smoothly and with minimal effect on chassis position or attitude.
It's the closest thing to a "paddle shift" you will find on a motorcycle!