Old soldier's headgear (3,3)

I believe the answer is:

tin hat

(Other definitions for tin hat that I've seen before include "Headgear, worn for protection" , "Protective helmet once worn by constuction and mine workers" , "Finish it off to put the protective headgear on it" , "Soldier's helmet" , "Steel helmet (informal)" .)

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.