★★★This mens merino wool+silk base layer bottom is made of natural materials --Merino Wool and Muberry Silk. add spandex to maintain the elasticity of the clothing for a snug fit,ultra soft smooth, breathability, and moisture-wicking &odor-resistant properties , beneficial for skin health and will not cause any allergies or skin irritation, wearing the thermal long underwear bottom , as a base layer for any activity.such as hiking, running, hunting, fishing, skiing, snowboarding, going to the gym, or simply just sitting at home ,comfortable,heathly and suitable for most people.perfect as a present. You can give it to your boyfriend/husband/father on Christmas/Thanksgiving/Birthday/Anniversary.