From Backpacker.com

Active insulation—layers designed to keep you comfortable both when you’re moving and when you’re not—has been around for a few years now. They’re nifty, but wind-blocking nylon shells mean they’re never quite breathable enough to live up to their promise as a layer you can wear in any conditions. The Ventrix, an insulated softshell, changes that with what we might call “smart” insulation.

The stretchy, DWR-treated fabric has tiny, laser-cut holes in high-heat but wind-protected areas, like the underarms and upper back. When you’re standing still, the holes remain closed. But when you move, tensioning the stretchy, nylon/elastane outer, the holes open, allowing airflow. So for every high reach and pole plant, the holes dump heat and sweat vapor, which kept us comfortable whether we were skinning uphill under the sun or ripping turns on the way down. The fit is athletic, the scuba hood nestles under a helmet, and the DWR treatment repels light precip.

Usually, managing layers eats up daylight, but the Ventrix kept us moving and comfortable from our first run to our last.

— Original Article: https://www.backpacker.com/gear/ventrix-hoodie