Features our unique T3 construction with maximum sole and shin padding for protection and warmth. The combination of merino wool, prim aloft yarn , and nil it energy results in faster drying and wicking than just merino wool while still maintaining a comfortable feel against the skin. Best suited for cold weather activities where moisture is an issue. The inner layer of prim aloft eco polyester yarn is made up of ultra-fine polyester fibers which are finer than cashmere, resulting in a luxuriously soft feel while providing unparalleled moisture wicking. When hiking, climbing or doing any aerobic activity, your body works up a sweat and emits heat and perspiration, but when you suddenly sit idle, you can easily start to freeze with an insulation that absorbs water. Prim aloft eco polyester yarn fibers wick moisture away from the skin and trap body heat. Merino wool provides all-day warmth while wicking moisture away from the foot to keep you dry. Knit with heavy cushioning all throughout the sock for warmth and a snug fit within your boots that prevents irritation from the inner boot liner. Lastly, nil it energy is a special type of nylon that converts heat emitted by the body and reflects it back to enhance muscle elasticity and oxygen absorption. It is durable and long-lasting. Repeated washing will not decrease the effectiveness of the technology. This is a fantastic sock for skiers looking who need warmth, padding, and dryness on the slopes.