Ball Mount for Contour Track/Rail

20mm Machined Track/Rail Style Mounting Ball PRODUCT DETAILS Pack Contains: 1 Machined Aluminum 20mm Ball anodized black with threaded stud 1 Slide in track/rail insert  Simply slide the insert into your Track Style E-dock (not tube style), then thread the ball into it until tight.  This ball does not work with tube style mounting systems. The drop in track/rail insert can be black or silver, depending on what is available from our supplier at the time we source them