Hope pro 4 mtb rear hub qr axlehopes reputation for producing bombproof hubs is well entrenched this hope pro 4 mtb rear hub qr axle hits the mark again with a disc brake compatible pro 4 hub super strong super smooth and totally reliable hopes pro 4 mtb rear hub qr can be used to replace your worn hub or to act as the tireless workhorse of your custom wheelset featuresmaterial machined forged t6 aluminiumfour pawl ratchet with 44t engagement 8 2sealed stainless steel cartridge