An airshifter is used for mostly drag racing, unless you have one just for shifting gear doing wheelies. It allows the operator to shift gears without using the clutch or shift lever. An air cylinder is mounted to the bike and to the shift lever When a button is pushed, your engine kills, the cylinder activates by retracting upwards causing the bike to shift, and then the engine comes on. This all takes place within milliseconds. You can purchase them through any dealer or hop-up shop. They offer many kinds such as; MRE, Pingle, and a few others. The average cost is around $300.00 for the whole kit. You'll need a MPS box to adjust the delay. The advantage to using these is that you'll never miss a shift by operator error on shifting, plus of course it's quicker. I'm not a bike tech by no means what so ever, I'm sure that someone else can help out with your questions better.