Spec 55-J-14, adopted by the US Navy Bureau of Aeronautics in the late 1940s, was the first jacket to be called the "G-1." As many as 11 contracts for the 55-J-14 were signed between 1948 and 1951. The design that began with the M-422 was standardized in a series of jackets that went through the joint Army-Navy AN6552 and AN-J-3A, and the appearance and details of these jackets have basically remained unchanged. This is a testament to the integrity of the design and details that were adopted from the outset. In addition, the G-1 is the longest lasting leather flight jacket and a source of pride for the US Navy, even though synthetic fibers have now become the mainstream of flight jackets. This G-1 is the model produced by A. Pritzker & Sons, who also manufactured and supplied the B-15C to the Air Force during the same period in 1951. There is no size description on the main woven label, instead, a size label is inserted under the main label. Leather tanned with full vegetable tanning tends to be hard and rigid, but goatskin with its flexible fiber quality overcomes this.