Cast aluminum construction with nylon pulleys on a 1/4" stainless steel axle, this truck is designed to be used on flagpoles that have up to a 3 1/2" outside top diameter with female fitting installed. The bottom of the spindle has a 1 1/4" NPT threading male end that goes into the top of the flagpole while the top spindle is designed to accept an ornament with a spindle and it is then secured to the truck with a stainless steel set screw. These trucks utilize self-lubricating ball bearing assemblies for ease of rotation, product life and strength. Maximum halyard diameter is 5/16". Fits COMMERCIAL grade flag poles with a 3 1/2" outside diameter.