Abstract: A device for using power of a moving fluid or generating movement in a fluid such as a wind turbine is provided with radially placed blades and a pitch change system. The pitch change system comprises a central pitch change shaft and guide shafts, with a sliding means slidably coupling the guide shafts to the pitch change shaft. Additionally, a blade coupler couples the sliding means to the blades, whereupon controlled movement of the pitch change shaft along its central axis causes a corresponding change in the pitch angle of the blades. The guide shafts are preferably provided with alignment means.