Shimano's SLX Rear Freehub is ideal for building the perfect all-mountain rear wheel. It sports a 142x12mm through-axle so you can go big without fear. And, the hub features durable cold-forged aluminum and easy to service cup-and-come bearings to ensure that whether you're hammering or sticking sick landings, it will hold up ride after ride. Shimano's Center Lock spline makes mounting the disc-brake rotor super easy, too. And the Micro ratchet mechanism gives you fast engagement, perfect for pedal kicks, picking your way through techy sections and split-second accelerations.