Flak Jacket

The flak jacket is usally worn by Chunins and Jonins over their normal clothes in most villages, although the design varies among the villages. For instance, the Leaf shinobi wear a green jacket where the Sand shinobi wear a beige jacket and the Star Shinobi where a blue jacket. Though they are called jackets, they look more like a vest. The jackets are among the most iconic pieces of shinobi equipment and a ninja soldier icon as well. Most of them have pockets for easily accessible scrolls. Note that while the current flak jacket in Konoha has pockets, the older ones do not. They are also called "tactical vest".

Colors
Konohagakure - Green

Sunagakure - Baige

Hoshigakure - Blue

Trivia

 * Only two of Naruto's generation ninja wear this jacket (Shikamaru and Lee), while others do not, even Neji continues wearing his robe, perhaps as a symbol of his clan.