"Silk Women's Silk Thermal Underwear Sets,silk Long Underwear Sets" f54 1. As a lightweight thermal fabric, it can be easily worn as a base layer, wicking moisture while maintaining comfort. From sunrise to sunset, you'll be able to comfortably wear them no matter what comes your way.2. Durable 4-way stretch rib-knit hem and snug fit will flex, fit and move with your body to maintain range of motion and comfort. Whether you're camping, hiking, snowboarding, exercising, working, or just relaxing, this cozy thermal fabric has you covered.3. No matter the season, this lightweight thermal fabric will be a must-have addition to your wardrobe as merino wool has natural hygienic properties that will keep you fresh all day, no matter the weather.4. The excellent warmth-to-weight ratio of this thermal fabric makes it ideal for traveling and packing when you want some lightweight trousers on your adventures.5. Double-sided long-lasting heat storage fabric Double-sided brushed type, winter and winter base, warm without load, more suitable for body temperature environment 0-15 degrees