The Primary cassette hub replaces the Coaster Pro. It's the ultimate mountain bike cassette hub that will work great in both horizontal and vertical dropouts. The female axle system will keep the rear end of a frame much more stable, and can be used in horizontal dropouts without any axle positioning systems. It’s light enough for racing and strong enough to take big slopestyle jumps. This hub is fully sealed, runs on 4 bearings and features an oversized alloy 7075 axle. The hub is held securely by 3/8” bolts. The advantage of using big bolts is significant: there is no weight penalty as they are drilled for weight saving and what's also important is that they are almost flush with the dropouts so there is little chance to hurt your ankles. The bolts have 8mm hex sockets so you can tighten your rear wheel with an Allen key. NS have used the best alloy for the cones and even reinforce them with steel inserts.