Men's Optima JacketDescription We took our experience using waterproof breathable laminated fabrics, and crafted a light weight seam sealed jacket with large direct core vents that can be used when it's warm or when it gets cold and wet. Unlike traditional venting systems that send air to the outside of a liner, the direct core vents send air directly to the wearers body and is therefore more effective. when the weather changes from good to bad, all you have to do is