Leather Sweatbands Labels from WW2. Combination Image. Photograph

Iconic labels from the Bancroft Flighter and Pak-Cap Crusher Caps of the US Army Air Force of WW2 and the Luxenberg visor caps of the same era.

The internal leather band located inside a hat—just above the underbrim—is called a sweatband.

Depending on the context, it is also frequently referred to as:

Inner band

Leather liner (specifically when referring to high-quality leather variants)

Its primary functions are to provide a comfortable, snug grip against the head, keep the hat from blowing off, protect the outer material from oils and perspiration, and help the hat maintain its structure. The Bancroft Pak-Cap Label actually sits behind the outer Insignia at the front of the cap and is not located on the sweatband. All of these are distinct from Cap Manufacturer labels which are placed centrally in the lining of the crown