Exoshell 40using a unique 3 layer construction exoshell fabrics achieve a colossal breathability rating of up to 60 000gm17824hr and an impressive waterproof rating of 18 000mm the key to the exoshell familys impressive breathability lies in the ultrafine fluorine free membrane which is up to 50 thinner than standard membranes protected by a super fine denier tricot laminate the progressive construction of exoshell40 not only provides impressive breathability ratings but at a mere