The Allen Large Aerovane is designed for use on dinghies, flag poles, and motorboats. Its mast mount collar, made of flexible plastic, can be easily attached to a variety of spar diameters. The elastic loop and stopper ball provided make it simple to attach the collar to the mast, and the built-in counterweight ensures accurate indication of apparent wind angle. Additionally, the counterweight prevents the Aerovane from flapping in strong winds. Its size has been carefully crafted to balance readability and drag reduction, with a white underside for easy viewing from the deck of the boat. Assembly is straightforward - simply push the Aerovane onto the rod until you hear a click. Removal is just as easy - pull with force from the rod. To secure the Aerovane to the top of your mast, the A4066 Burgee clip is also required.