Light Novatec B2 SRAM XDR Driver 6 pawl upgrade freehub with alloy body to take road and gravel cassettes needing a XDR Driver type (most cassettes with a 9t or 10t small cog but NOT INCLUDING Shimano 12 speed cassettes which need a Microspline freehub type. 

Standard B2 freehubs have either 3 or 4 pawls with 27 points of engagement. This upgrade freehub uses 6 pawls with 54 points of engagement for a finer ratchet action.

Compatible cassettes are usually made by SRAM.

This freehub will NOT work with any cassettes needing a Shimano HG pattern splined freehub. 

Will fit the following Novatec hubs:

D712, D702, D772, D792, D882, D722, D732, D621, D622, D992, DH82, DH12, DS52 6 bolt disc hubs 

XD612 centrelock, D772 centrelock, D792 centrelock hubs 

F482, F482SL, F582, F582SL, F682, F782, AS522 rim brake hubs

Also Superstar Switch and Superstar Switch Ultra and the Prime hubs which are rebranded Novatecs (be careful, not all Prime hubs are made by Novatec)

There may be other hubs which this freehub will fit but it is up to the purchaser to check the compatibility.