Flame Retardant is a fire gear perk that puts out the flames on you automatically when you catch fire. It saves you from the burn damage that keeps ticking while you are alight.
When you catch fire, the flames go out on their own instead of burning until you put them out. You lose much less health to burning.
Good against flamethrower soldiers and in fire-heavy fights. It uses your hands slot, which competes with aim and gadget perks.
Fire Protection or Major Fire Protection on other Fuego pieces covers the damage side.