The new men’s Arc’teryx Keibo jacket is simple, technical, but most importantly it fits like a glove. I do not expect less from the world’s premier outdoor clothing manufacturer. As with most high end jackets, GORE-TEX is the material of choice. Gore is a membrane material that contains over 9 billion microscopic pores per square inch. The little tiny pores are 20k times smaller than a water drop, but 700 times larger than a water vapor molecule. The GORE-TEX membrane gives Arcteryx unlimited waterproofing and unlimited breathability. By adding Coreloft as an insulation barrier the jacket maintains it’s thin profile but still provides a new level of warmth not usually seen in this category. The storm hood is big enough to fit over a helmet for those windy and wet days. The Keibo is quite honestly the best jacket that I have seen in the 2013 line up thus far.