Captain Ironsides' hat

 is an unique headgear-type item in Fallout 4.

Background
Preceded by the Tricorne, the Bicorne is a form of hat widely adopted in the 1790s as an item of uniform by European and American military and naval officers. In practice it was worn by most generals and staff officers, and it survived as a widely worn full-dress headdress until at least World War I.

Characteristics
This item provides the following: Perception +1, Charisma +1.

Locations

 * Worn by Ironsides
 * This can be found in the southwest corner of the Custom House Tower courtyard following the conclusion of the quest Last Voyage of the USS Constitution.