Optical Trigger Wheel for Nissan SR20DET or KA24DE by DIYAutoTune Convert your Nissan CAS to a more MegaSquirt-friendly arrangement with our bolt in optical shutter wheel This one replaces the ring of four slits with a 24-1-1 wheel that behaves like a 12-1 crank trigger We added an outside slot to provide a cam sync where the 360 degree slot ring works You can use just the inner ring to get a rapid sync-up, or use the outer slot to allow for sequential injection or coil-on-plug Intended for use with MS1 and MS2