Nicky Bigs Novelties™ Adult Propeller Cap Bring some fun to any event with this spinning propeller cap. Propeller Ball Cap Hat Nice feel and look features a real spinning propeller on top. This multi color hat does not vary in color but the propeller color does and there is no way to guarantee the color of propeller from hat to hat. It will be chosen at random. Size: One Size Fits Most Adults with elastic back allows for head sizes 55 CM to 61 CM (snug) in circumference. (Approximately 21.6 to 24 inches). See size hat chart image.