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