Wrap yourself in the warmest base layers made with Heat Boost graphene technology, a next generation of enhanced fabrics. A 4-way stretch knit jersey fabric with enhanced with graphene yarn for 30% more warmth than traditional base layers. Graphene possesses thermal conductivity, moisture wicking, and antimicrobial properties naturally. It harnesses your body's energy, absorbs the heat and releases it back, surrounding you in a lasting radiant warmth. Combine with a knapped hand feel, a form fit, and non-chaffing flat lock seams, and this base layer is as comfortable as it gets. Use the hidden thumb straps to keep the sleeves in place while layering. You'll feel the difference with this base layer shirt on every cold weather hunt. 1 year limited warranty