Back in the 70's I had some fishnet underwear. A little crude, and made of 100% cotton, but functioned well. This update of that old premise really works well... Summer or Winter. Improved ventilation in the summer, and in the winter with everything zipped up, it adds a layer of air next to the skin (lest we forget air is the best insulator), and no clammy feeling from sweat drenched base layers. Stretches, so don't be afraid to buy one size smaller. Well worth the $35 sale price. Highly recommended!