Instant Transfer System 4. Using 4 pawls working 2 by 2, the system provides a more dynamic ride, thanks to a very fast engagement. Its versatility makes it compatible with all kind of frame retention system. - Better energy transmission: fast engagement, only 7,5° freeplay between two engaged positions - Stiffer: 17mm monobloc axle - 12mm through axle compatible to fit any kind of frame retention system