Built With The Most Advanced Performance Fabric: NuyarnA(R) DragonWool(TM) is warmer, lighter, stronger, smoother, softer, longer-lasting, stays warm even when wet, and dries 4x faster than normal Merino wool! Dries 4 Times Faster: DragonWool utilizes the highest quality merino wool against your skin to wick moisture away from your body, and then the jersey face polyester quickly pulls that moisture from the wool and evaporates it into the air! Actively Breathable: DragonWool keeps you warm when you need to be, and lets you breath and cool when you are active! Merino wool and the jersey face polyester materials are woven together to form one fabric- it&';s not bonded together, but woven together to create a synergy that actively cools or warms your body with different activity levels! Add/Remove Without Removing Your Boots: With a full-length stretch zipper down each leg, you can easily add or remove the thermals without taking off your boots! This gives you the flexibility you need to quickly adjust your layers to accommodate for weather and temperature and stay comfortable! *note- DragonWool is a performance first fabric, and not designed for excessive abrasion.