Layering is a science with Sitka's system of next-to-skin products. Each of the fabric weights-light, mid, and heavy-wicks away moisture to keep you warm and dry, while Polygiene® technology safely and permanently neutralizes odors using naturally antimicrobial silver salt. Build the foundation of your system with a specialized base layer designed to suit your environmental conditions. Sweat is odorless but helps create the perfect environment for odor-causing bacteria to multiply. When sweat mixes with odor-causing bacteria on fabrics, odor results.Polygiene uses naturally occurring silver salt (silver chloride) made from recycled silver, a highly effective antimicrobial agent, to safely inhibit the growth of odor-causing bacteria and fungi. However, Polygiene does not affect the natural bacterial flora of your skin. And without odor-causing bacteria, you stay fresh.