The type A-1 jacket, standardized in 1927, was a summer flight jacket that was produced until 1931 when the A-2 was newly adopted. The front is closed with buttons, as it was designed before zippers came into practical use. Sheepskin was used for the A-1, and while it is flexible and easy to move around in, it is slightly inferior in terms of strength compared to horsehide or steerhide. As such there are very few of original jackets still in existence and encountering one would be a miracle. This A-1 is made of horsehide, a leather stronger than sheepskin. The horsehide undergoes a full vegetable tanning process and is hand-finished with aniline dyes by artisans using a baren. The horsehide has an irreplaceable look and feel when it is worn and wrinkled and when it matches the uneven coloring of the finish.