Boonie hat,
boonie brim or
Boonie is current authorized head gear for military personel. It is a full brimmed hat, and provides limited protection from the sun and rain to the head and neck.
These hats were origionally made popular during the Vietnam Conflict worn by Special Ops soldiers and
LRRP personel. The Boonie hat replaces the standard Army issue "soft-cap" and the Marine Corps "cover". Sometimes called a "flop-hat"