Four interchangeable ratchets allow riders to tune their rides for their personal performance needs. Whether it be maximizing efficiency, response, or reliability, we have a solution. - 40t - 9 Engagement - 60t - 6 Engagement (Stock Road/Gravel Offering) - 80t - 4.5 Engagement - 100t - 3.6 Engagement Compatible with ENVE Innerdrive Hubs only.