The EN 343 norm specifies the demands and the performance prove methods of the protection articles against the cold and temperatures inferior to 5ºC. Basic thermic isolation measured. The value is based in the maximum temperature of the use to an activity level and a durability of the exposition determined to the test (A or B). Permeability class to the air (0 to 3): It’s the article’s impermeability level. Evaporative resistance class: It’s the level of “breathness” of the arcticle.