Windex 10 Sport - EXTRA WIND VANE ONLY. Windex wind vanes continue to offer exceptional performance at the best value of any wind indicator worldwide. The secret is in the sapphire jewel suspension bearing, large fin-low inertia vane, and easy-to-read, fully adjustable tacking tab system. Reflector tape on the vane and tacking tabs make Windex 10 Sport easy to see day and night. Windex vanes are sturdy and when installed properly, offer many years of use. They have been wind tunnel tested to wind speeds of 80 knots! Windex 10 Sport has a 10" (25 cm) vane.