This is an evolved "MK4" flight jacket, the successor to the Royal Air Force (RAF) masterpiece, the MK3. Size: 8 (Shoulder width 52cm, Body width 65cm, Length 63cm, Sleeve length 64cm) 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 zip is completely covered with a storm flap to completely shut out the wind. The large-capacity "slash zip pockets" located at the abdomen are easy to access and combine practicality and 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 inside of the back. This is taken out from the back and passed to the front to be worn during parachute descents to prevent flapping. All buttons use "parachute buttons." These buttons were developed by the military so that they would not snag on parachutes during a paratrooper's descent. By not using thread as usual, there is no risk of the thread getting tangled, and ease of removal is also considered. As you can see, this jacket has a high-spec construction that refines practicality. The use of Gore-Tex in the fabric this time has made its functional beauty the highest peak. The sizing is also a short length typical of flight jackets. This is to consider ease of movement so that the hem does not interfere when sitting in the cockpit. This length gives a relaxed body width while skillfully suppressing the clumsiness of military wear. This refined size balance is also 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.