Flak Jacket

The flak jacket (Tactical vest) is usually 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 wear 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, which you can store scrolls in and get with only one hand. Note that while the current flak jacket in Konoha has pockets, the older ones do not.
 * Debut (Anime): Naruto Episode 1
 * Debut (Manga): Chapter 1

Colors

 * Konohagakure - green
 * Sunagakure - beige
 * Hoshigakure - blue
 * Kirigakure - purple
 * Otogakure - dark grey
 * Takigakure - skyblue

Trivia

 * Only two of Naruto's generation (Shikamaru and Lee) wear this jacket while others wear their own customized outfits.