This article is a stub. It is short and in need of expansion. Why not help out?
Modern day armored vests were originally known as "flak jackets", and were used by bomber crews to protect against high-caliber proximity-detonated anti-aircraft shells (flak). After research during the Vietnam war showed that 2/3 of casualties were from fragmentation, not bullets, body armor saw a proper return to the frontlines.
Reduces explosive damage caused upon the player and his squadmates
"Reduces the damage taken from explosives and shrapnel by providing additional coverage to high risk body parts."
— Battlelog description
FLAK is a Specialization in Battlefield 3. It reduces the damage taken from explosives and shrapnel by providing additional coverage to high risk body parts. It will not, however, protect against direct hits.
Decreases the amount of damage taken from explosives by 15%.
The solo specialization is unlocked at rank 8, while the squad specialization is unlocked at rank 29.