Fabricated from a black wool on the exterior, featuring the classic high peak, the upper edge trimmed in black wool covered piping. It has a 38 mm wide band in black wool displaying a repeating thatched-look pattern around its circumference. There is a 73 mm (w) x 63.5 mm (h) Royal Naval Air Service officer's cap badge on the front, with a silvered eagle in the centre, surmounted by the George V crown in silvered and gold-coloured bullion wire, in various textures, the voided areas of the crown in maroon felt, with touches of red and green embroidery along with black threading giving definition to the base of the crown, the surrounding leafing in rolled gold-coloured bullion wire, in two varieties, on a black wool base. The stiff visor is finished in a black patent leather on the upper, with a reinforcing strip in black patent leather stitched in place on the edge. There is a black patent leather strap with dual adjustable sliders that runs across the front between the black fabric wrapped buttons on either side.
The underside of the visor is in a hunter green synthetic material, the sidewalls lined in cobalt blue rayon, the underlying framework in a thatched wicker-like material. It incorporates a 45 mm wide sweatband in leather, the upper with a faded light brown finish, the ends of which are sewn together via black threading at the rear, with the name "B. Warren." inscribed in black ink on the right side. The dome is lined in navy blue cotton and bears the Royal "By Appointment" insignia and the "GIEVES Ltd" manufacturer's mark in gold-coloured ink, the dome covered by a celluloid moisture shield. The cap measures 235 mm in width x 270 mm in depth x 115 mm in height, exhibiting wear on the maroon felt on the crown, the eagle loose versus the base on the cap badge, scattered nips in the black wool band, crazing on the black patent leather upper of the visor and the strap resting upon it, cracking in the celluloid moisture shield, along with extensive soiling on the underside of the visor and the sweatband from active use. It is of very fine quality manufacture, the bullion of the cap badge remaining pristine and without interruptions, the cap itself free of mothing. Fine.
Footnote: The Royal Naval Air Service (RNAS) was the air arm of the Royal Navy, under the direction of the Admiralty's Air Department, and existed formally from July 1, 1914 to April 1, 1918, when it was merged with the British Army's Royal Flying Corps, to form the Royal Air Force, the world's first independent air force.