NWT Features: Superstretchy knit fabric combines unbelievably soft, responsibly sourced merino wool next to skin with a durable synthetic outer material Windproof front panel's wind permeability is rated at 1 CFM Drawcord on the interior waist lets you fine-tune the fit Reflective elements help improve visibility while you are out on your run or hike Drop your cellphone in one of the pockets on the side; zip your car key in the zip-secured pocket Flatlock seam construction is designed to minimize chafing The wool contained in this product is certified to the ZQ Standard, which has been granted equivalency to the Responsible Wool Standard