IFR Nomex®IIIA 6 oz Deluxe Flame Resistant FR CoverallsThe NSB is one of the first IFR styles. It's almost the same as the 109 but has a CAT1 rating. 6 oz. 93% Nomex, 5% Kevlar, and 2% Carbon added for improved anti static performance Material is inherently flame resistant Breakaway zipper Flame resistant mesh on H2S monitor pocket No melt, no drip Velcro Lowered X striping on back to allow room for company logo or hooded undergarment CAT 1 Nomex is inherently flame resistant, and meets the following