vintage unlined black leather cap chin strap aviator's helmet flying or motorcycle

Vintage soft leather helmet for pilot or motorcyclist, early to mid 20th century.

We were told this could be vintage Harley Davidson - we know it's from an estate in the Milwaukee Wisconsin area, so I suppose it's possible.

This has no label at all - it's large, fits a 21"-22" head. The leather is thin and supple, lamb or goat skin, I think.

It's in excellent condition, no rips or tears to the leather, strap and buckle show no obvious wear or stretching. Very clean.