The Rotary single features the unique bolts from the Rotary Pro hub with hex heads. We decided to employ a female system in this hub. The steel thru-axle with nuts was replaced with a lighter and stronger oversized alloy 7075 axle and steel bolts. In other words this hub uses the same system that proved itself in our Rotary Single Pro rear hub. The female axle system will immobilise the wheel in the dropouts no matter what, and there is much less chance to hurt your ankles on the bolts. Overall, we managed to produce an incredibly light and strong hub in an economical price range.