Alpinestars Thermal Tech Top The Alpinestars Thermal Tech top is part of Alpinestars range of base layer underwear developed for layering purposes to provide core temperature regulation and comfort for all types of riding conditions. The Warm Tack base fabric used for the top is Nano treated to increase circulation of the capillaries to promote warmth. The fabric is also treated to wick away moisture and keep the body comfortable. The compression fit reduces muscle fatigue in the upper body increasing riding comfort Features Developed for cold weather riding conditions Warm Tack fabric construction Fiber is a stretch Nylon, Nano treated for effective heat conductivity and moisture wicking Ergonomic flat lock seam construction Compression fit design to reduce muscle fatigue in the top. Printed ASTAR logo