The Hobie Island mast head vane will help keep you going in the optimal direction. Mylar wind indicator for the Adventure Island and Tandem Island. Up on the mast head is the least disturbed wind flow, so the optimal location for a wind direction vane. As the wind changes direction or oscillates, you need to adjust heading and or sail trim for best performance. No tools required. This wind vane is designed for all Hobie Islands when not using a spinnaker kit. Simply slips over the mast head and tightens in place with a thumb screw.