A proprietary blend of fine micron Helle Rambouillet, and a mix of cellulose and polyester produces an ultra fast wicking and naturally cooling single jersey fabric. Merino Wool has taken over the base layer industry over the past few years, and there is no denying that it far outperforms synthetics, especially on those longer duration hunts. That being said, as all products do, Merino in itself has some shortfalls. Merino Wool in its entirety, is somewhat fragile, and over time breaks down slightly faster then synthetics. It also does note dry quite as fast, especially when carrying a pack where it is in constant contact with sweat. Vapor Wool, utilizes the best of both worlds. By taking advantage of Merino's strong anti microbial properties, adding to it the durability and quick drying properties of both natural and synthetic fibers. This technology is being used across the industry both by outdoor enthusiasts and the Military. For most of us, a Merino Top can be used both as a Baselayer, and a mid layer for hiking. Pair this Vapor Hoody up with a short sleeve Merino top of your choice and your covered!