That's simply the extra "fancy" chief of staff/operations cap that all service chiefs wear. All services do some overly grandiose designs all over it for the senior most leader. It's a bit ridiculous. Go take a look at the other Services hats for their Chiefs. Air Force has thunder clouds all around their center band, for example. The Army Chief has oak leaves all around. Traditions force a lot of design elements. The rank and file members get "normal" caps without the bling.