More than just a base layer, it´s a four-season shirt with breathability for staying on the move.Winter layer, for sure.Spring breathability, absolutely.Quick-drying for summer fun, you bet.The men´s Burton Lightweight X Base Layer Crewneck brings breathability and comfy stretch to adventures big and small.It´s the base-layer shirt you can wear to hit the hill, go for a hike, or just wear under your hoodie ´cause it feels good.Features:Slim fit sits close to the body, with room for the garment to move with you.Lightweight 100 Living Lining® provides consistent temperature regulation without adding bulk or weight.Four-way stretch fabrication for enhanced mobility.Quick drying and highly breathable.bluesign® approved non-biocidal finishes keep odors at bay.Chafe-free softlock seams for added comfort.bluesign® approved materials use only safe chemicals and reduce impact on both humans and the planet during manufacturing.