What is a truck? It is the top part of the flagpole commonly known as the pulley. All flagpoles have specific trucks or pulleys that are better for their use. Smaller flagpoles or sectional flagpoles often use the eyebolt and pulley system or a side mount pulley for the halyard (rope). Larger flagpoles use a truck unit that houses the pulley within its cast aluminum frame. This eyebolt & pulley unit has a zinc plated 3″ eyebolt and brass coated sheave (pulley). The set comes with two nuts and washers. The largest recommended halyard (rope) size is 1/4in.