What is the optional FIA 3rd layer addition exactly?
The optional 3rd layer for the Pyrotect FIA rated custom racing suit is constructed of Non Woven Perforated Middle Layer.
It adds additional fire protection. It also adds additional weight. An additional 50 g/m2 to the weight of your suit. (g/m2 is: "Grams per square meter [of fabric]" which refers to the weight of the suit.) (50 grams equals approximately 1¾ ounces)