This is the official LVFR Duty Nomex IIIA shirt.  Its made of 4.5 oz 100% Nomex IIA plain weave fabric. Its Certified to meet NFPA 1975 Regulations. It also includes  a panel front with hidden snap closure for easy access, two mitered breast pockets with hook and loop closure, a left pocket flap that  includes a pencil/pen slot,  and a fuse banded dress collar and cuffs.