Cast Aluminum construction with a 3 7/8" outside diameter aluminum pulley on 1/2" stainless steel axles. This truck is designed to be used on flagpoles that have up to a 6" outside diameter with female fitting (below) installed. The bottom of the spindle has a 1 1/4" NPT threading and is screwed into the top of the flagpole while the top spindle is designed to accept an ornament with a spindle threading of 1/2"-13NC as standard but can be supplied with other sizes of threading. The ornament is secured to the truck with a 1/4"-20NC stainless steel set screw. The truck body rotates on a 26 stainless steel ball bearings on cast races. Maximum halyard diameter is 3/8".