Cast aluminum construction with cast nylon pulley (1 7/16" outside diameter on OTH, OT1 and OT25; 2" outside diameter on OT2, OT3, and OT35) on a 1/4 " stainless steel axle. Designed to slip over the top of the flagpole and be secured by stainless steel set screws (one 1/4 " - 20NC on the OTH; three 5/16" - 18NC on the OT1, OT2, OT25, OT3 and OT35). the top of the truck 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 if desired. The ornament is secured to the truck with a size 10-32 stainless steel pan head screw. The recommended maximum halyard diameter is 5/16". Above item pictured in Silver.