Best Use: All Conditions The ½ zip hooded design allows for added heat release and ventilation while reinforced thumb holes keep the sleeves in place when adding a layer. The PRO Merino is a great choice for the hunters needing a versatile hardwearing shirt that is useful in a wide range of conditions. PRO Merino is the result of years of development with TMC and a breakthrough in mid-layer technology. The dual-layer knit construction positions 17.5-micron Nuyarn Merino next-to-skin with a quick drying, durable polyester eyelet outer face. The Nuyarn wicks moisture away from the skin and it passes through to the surface of the Polyester. The Polyester distributes the moisture over its surface, while the eyelet construction speeds the process and encourages airflow within the fabric. This moisture management is a mechanical process, and results in a piece that absorbs, disperses, and evaporates moisture 4x faster than pure merino or comparable weight blends.