Good old google, found this: Firefighting ensemble
The tunic
A firefighter's tunic is made from fire resistant, synthetic fabric which retains its structural strength after fire exposure, and resists cuts and tears. It provides a good level of protection without exacerbating the metabolic heat stress of the firefighter. It is designed to enable good flexibility and the collar has a long zip to ensure complete closure of the jacket to the neck. It provides a high level of thermal resistance protection without being overly heavy to wear.
