Cast aluminum construction with a cast nylon sheave on a 1/4″ aluminum axle. The flagpole truck body rotates on 26 stainless steel ball bearings on cast races. This single sheave flag pole truck can be used on poles with up to 4″ O.D. tops. The top of the spindle is tapped 1/2″ as standard to accept a gold ball or eagle. Maximum recommended halyard (rope) diameter is 5/16″.