Shimano DuraAce FH7900 Rear Hubs. Both the hub and freehub body have evolved to improve rigidity for efficient power transfer and quick handling. The bearings have been updated with a new toolfree bearing adjuster for quick bearing adjustments. The freehub has a durable titanium shell and quick engagement internals. Compatible with all 8 or 10speed Shimano cassettes Titanium freehub body and an aluminum axle Freehub body utilizes four pawls for quicker hub engagement Hub Dril