Windex is the perfect choice for all cruising and racing boats 15 feet (4.6 meters) and bigger. With 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 15 easy to see day and night. Windex 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 inches (24 cm) above the vane to discourage birds from landing.