The United States Coast Guard wears the combination cap, known as the combo cover, with the Service Dress Blue uniform (SDBs), the Tropical Blue uniform (Trops), and with all other formal dress uniforms. The cover is identical to that of the Navy with respect to the chinstrap and peak ornamentation. Its crown is white. The buttons securing the chin strap to the sides of the band are smaller versions of the buttons worn on the Coast Guard's uniform coats. The blue band around the cap includes blue fabric extending upward on the front of the crown to serve as a backing behind the device. In the case of enlisted personnel, this extension is a blue circle identical to that on the caps of naval officers and chief petty officers. In the case of commissioned officers, however, the extension is a more elaborate polygon to accommodate the officers' cap device.