Those are the two metal fixtures on the old WWII, Korean War, and Vietnam War M1 steel helmets (also called steel pots). Those two fixtures (one on each side of the helmet) are what the canvas chin straps were attached to.
M1 steel helmet collectors usually talk about "fixed bales" or "swivel bales"; apparently the "fixe bales" were the original type (design) and probably, collector's might value them more than the swivel type. By a process of elimination, there certainly wouldn't be any Vietnam War steel pots with "fixed bales." Those would all have to be "swivel designs."
The WWII & Korean War M1 helmets are the same helmet, since Korea occurred only 60 months after WWII, and they made 22 million of them during WWII.
Sun helmet (they were designed to keep the head cooler in hot climates).
a helmet obviously
crash-hat
A hard hat to protect the head is a helmet.
zakum helmet
A crash helmet, one supposes.
It could be a wig, hat, headscarf, helmet, woollen hat, etc. Personally, I wear a woollen hat when it is cold.
HELMET
a helmet with a red cross on all sides.
White Cap Scholar's Hat Red Cap Safety Helmet Yellow Cap Police Cap Light Blue Cap Explorer's Hat Green Cap Captain's Hat Star Cap Sailor's Hat 1-Up Cap Silk Hat Purple Cap Outback Hat Blue Knit Hat Dutch Hat Orange Knit Hat Sombrero Pink Knit Hat Tyrolean Hat Purple Knit Hat Viking Helmet Red Pom-Pom Hat Cavalier Hat Badge Hat Pirate's Hat Straw Hat Jester's Cap Grandpa Hat Witch's Hat Paperboy Cap Red Ribbon Beret Blue Ribbon Dandy Hat Yellow Ribbon Hunter's Cap Heart Hairpin Detective Hat Star Hairpin Top Hat Moon Hairpin Puffy Hat Green Feather Bandana Blue Feather Swimming Cap Yellow Feather Wizard's Cap Red Feather Big Bro's Hat Purple Feather Li'l Bro's Hat Rainbow Feather Bicycle Helmet Halo Chef's Hat Royal Crown Combat Helmet Crown
The pith helmet was first used in the 19th century. The helmet was made of cork or pith and was worn by many Europeans in the tropics. The pith helmet is also known a Safari helmet or sun hat.
Headqear is a military term for "hat" or a helmet.