This is an evolved "MK4" flight jacket, succeeding the masterpiece MK3 of the Royal Air Force (RAF). Size: 7 (Shoulder width 50cm, Body width 63cm, Length 63cm, Sleeve length 63cm) Around 2010, the MK3 was improved and succeeded by the new MK4. The outer shell fabric was changed to 'GORE-TEX'. This dramatically enhanced the waterproof/water-repellent and cold-weather protection, resulting in a significant evolution. The distinctive large collar has a chin strap, which can be fastened to prevent wind from entering. The front has a double closure with a zip and buttons, and the fly front completely covers the zip to shut out the wind. The large-capacity "slash zip pockets" located on the abdomen are easy to access and combine practicality with design. The left sleeve is equipped with a padded "utility pocket" (pen holder). The cuffs are adjustable with Velcro fasteners to prevent wind from entering. A "stowable hood" is also included under the collar on the back, which can completely cover the neck like an anorak. The hood also uses Gore-Tex. A so-called "beaver tail" with Velcro closure is attached to the lower part of the inner back. This is taken out from the back and worn over the front to prevent flapping during parachute descent. All buttons use "parachute buttons." These buttons were developed by the military so that they would not snag on parachutes during descent. They do not use thread, so there is no risk of entanglement, and they are easy to take off. As you can see, this jacket has a high-spec construction that refines practicality. The use of Gore-Tex in the fabric makes its functional beauty the highest peak. The sizing is a short length typical of flight jackets. This is to allow for ease of movement so that the hem does not interfere when sitting in the cockpit. This length provides room in the body width while cleverly suppressing the clumsiness of military wear. This refined size balance is one of the reasons why this jacket is popular. It is a very popular and rare model. If you were looking for one, please consider it.