Our USA made standard airport windsock frames are a simple but reliable design incorporating an aluminum hoop and bail. A bail is important for two reasons. First of all, to assure the frame retains it's structural integrity and shape, secondly and most importantly to help the windsock retain its general shape for pointing in the slightest of wind. Because of their collapsible design, shipping costs are greatly reduced. These frames are ready to be mounted on a 3/4" male pipe thread.