Absolutely hi-end ultralight MTB single speed rear hub. 9T driver with patented Q-Lai drive transmission technology with 6 double independent pawls located in the hub body. This makes more space inside the driver for 3 bearings. Together with 2 bearings in the body this makes our Revolt Pro a really smooth rolling and strong hub. 9T driver works perfectly with 23T sprockets. 15mm 7075 aluminium inner axle has a female system with hollow Cr-Mo 3/8” bolts (for 17mm wrench or 8mm Allen key). Hub body made of 6061 aluminium. The push-in cones made of 7075 aluminium.