Picture a suit that looks like a superhero's suit, but made out of special materials that can protect you from fire. It's called a Fire Resistant Environmental Ensemble.
This suit is like a safety jacket that firefighters use when they are fighting fires. When firefighters go into a burning building or work close to it, they need protection from the fire's heat and flames. That's why they wear this suit.
The suit is made of many layers of special materials that are fireproof. Fire cannot burn through these materials easily, and they don't catch fire easily. The layers also help keep the heat out so firefighters can work longer before getting too hot.
The suit has different parts to protect different parts of the body. The helmet protects the head and face, and it has a clear visor so the firefighter can see through it. The jacket covers the torso, arms, and legs. The boots and gloves are also fireproof.
Firefighters wear this suit like a regular set of clothes, and it's easy to take off when they're done. Without this suit, firefighters wouldn't be able to go as close to fires or work as long because they wouldn't be protected.