Mounting to the top of the mast, suitable for pole length up to 21 m. With sapphire bearings and reflective markings on winder wings and indicators. Option to add Windex Light. Length: 380mm. The secret of Windex is precisely balanced wind wings, small friction bearings and good visibility. Windex responds to the power of 2 knots. If possible, the angles can be adjusted to allow optimum wind rates to be read. Subtraction is facilitated by the ability of the human eye to recognize asymmetry. Windex 10 and Windex 15 are flags to be reflexive so they can be optimally read at night. Windex is tested in the vein channel for up to 80 knots. However, if it ever "hasted", spare parts are available.