Davis Instruments 15 Wind Vane Windex. The secret is in the sapphire jewel suspension bearing large fin-low inertia vane and easy-to-read fully adjustable tacking tab system.WindTrak is the perfect choice for all cruising and racing boats 15' (4.6 meters) and bigger.Reflector tape on the vane and tacking tabs make WindTrak 15 easy to see day and night. WindTrak vanes are sturdy and when installed properly offer many years of use. They have been wind tunnel tested to wind speeds of 80 knots WindTrak 15 has a 15" (38 cm) vane. Includes through-bolt or drill and tap mounting socket; 5/16" -18 stainless stud washers and nut. Stands 12.75" (32 cm) tall and weighs just 3.6 ounces (101 g).A bird-proof spike extends another 10" (24 cm) above the vane to discourage birds from landing. Specifications for Davis Instruments WindTrak 15 Wind Vane: Manufacturer: Davis Instruments Application: Outdoor Fabric/Material: Stainless Steel Height: 15 in Color: Black Weight: 3.6 oz Package Contents: Davis Instruments WindTrak 15 Wind Vane Davis Instruments 3150: 15 Wind Vane Windex