WindTrak 15WindTrak 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.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: Type: Wind Indicator Instrument Function: Wind Box Dimensions: 2"H x 5"W x 16"L WT: 0.5 lbs UPC: 011698315000