Seal brown is a rich dark brown color, resembling the color of the dyed fur from the fur seal.

The specifications for the U.S. Army Air Corps Type A-2 jacket (regulation summer flying jacket), adopted in 1931 and the most familiar among all leather flight jackets, stated that it should be made of horsehide tanned to seal brown.

[citation needed] However, initially, oxidation during the dyeing process caused the jackets to end up russet (a lighter, reddish brown) in color.

[citation needed] Later in the decade, they were able to prevent oxidation during dyeing, and the jackets produced were a proper dark brown.

[citation needed] Seal brown is one of the official colors of Lehigh University, Brown University,[2] the Cleveland Browns football team,[3] and the engineering honor society, Tau Beta Pi.