These cast-aluminum fittings cap the top of the flagpole and hold pulleys in place. The bottom of the stationary truck should be the same as the top, outside diameter of the flagpole. Revolving models allow flag to swivel around the flagpole and come on ½" spindle (1 ¼" NPT). Pulley screws into top of pole for 25' to 40' poles, preventing flag from wrapping around the pole. Standard female fitting on top of "truck" allows for an eagle or ball top. Made in the U.S.A.