The Definitive Cassette is the most advanced hub that Shadow has produced to date. 120 points of engagement and a 3 pawl engagement system that uses 4 notches on each pawl for an almost instant power transfer. Micro-notched pawls with individual leaf springs. 6061 alloy hub body w/ 2 precision sealed bearings. 1pc 9T chromoly driver w/ 3 precision sealed bearings. 14mm hollow chromoly axle