For External Halyard Flag Poles Cap Style Stationary Double Pulley. Cast aluminum construction with a 1 7/16 in. outside diameter cast nylon pulley on a 1/4 in. stainless steel axle. Designed to slip over the top of the flagpole and be secured with three 5/16 in. - 18NC stainless steel set screws. The top of the truck is designed to accept an ornament with a spindle threading of 1/2 in. - 13NC as standard but can be supplied with other sizes of threading if desired. The ornament is secured to the truck with a 1/4 in. - 20NC stainless set screw. The recommended maximum halyard diameter is 5/16 in.