If you put trust in wool, you can trust the ScentLokA(R) Merino 250 Base Layer System. Each piece offers 95% merino wool for dependable temperature management combined with long-lasting softness during your hunt. 250 gram weight serves well as either a base layer or mid layer. You get breathability on the movea |and warmth in the stand. Merino Wool is moisture-wicking and naturally antimicrobial for odor control. For optimal hunting effectiveness, the ScentLok Merino Wool system pairs easily with other ScentLok layers such as a Carbon Alloy jacket, shirt, or outer layer. 250 gram 95% merino wool (5% spandex) Dependable thermal management and moisture-wicking Naturally anti-microbial Pullover with 8" zipper for quick thermal management adaptation Flatlock seams for next-to-skin comfort Concealed thumb loops keep sleeves in place under other layers