Quickshifter
A quickshifter (or quick shifter) is a device that eliminates the need to use the clutch or throttle when shifting gears on a manual transmission. This can increase the safety and comfort of the vehicle and allow for faster gear shifting (usually shifting in less than 50 milliseconds) and is thus a popular performance enhancement for motorcycles. Working mechanism. Almost all quickshifters work on the same basis, a sensor detects the gear shift action, a microcontroller (CPU) processes the data (and calculates the timing) and cuts off ignition momentarily, resulting in a reduction of the load at the transmission  allowing the new gear to slip (and engage) into place. However the method of sensing and reducing the load can vary. Sensor. Most gearshift sensors work by measuring the pressure change (push or pull) on the shift rod. However, some sensors use a strain gauge, which is more expensive but may be more reliable and free from false readings due to vibrations since it has no moving parts. Microcontroller. The microcontrollers generally control the ignition and/or fuel supply to reduce the load from the transmission when needed. They can either be separate from the engine control unit (ECU) or a  single unit (meaning the ECU performs quick-shifting). They can provide a near-perfect gear shift in tens of milliseconds. Load reduction. The load on the transmission is generally reduced (or ""unloaded"") by cutting off the ignition and/or fuel supply in the engine, or by disengaging the clutch. Since load is reduced precisely (if tuned correctly) by the microcontroller, using the quickshifter is less damaging to the transmission than clutchless gear shifting without a quickshifter. Bi-directional quickshifter. A "bi-directional" quickshifter is a quickshifter that works on both directions of gearshift - upshifts and downshifts. Most quickshifters are bi-directional  (sometimes called "auto blippers"), so the term "quickshifter" alone is usually sufficient, however, "mono-directional" quickshifters that only work in one direction exist, like the "Kawasaki Quick Shifter" (KQS) on the 2016 Kawasaki Ninja ZX-10R and the 2015 H2/R, which works only for upshifting. Examples of performance oriented motorcycles using a bi-directional quickshifter are the BMW S1000RR and S1000R, 2017 ZX-10R and H2/R, Suzuki GSX-R1000/R, Aprilia Tuono, KTM Duke 390 etc.