The unique ingredient in these socks is the Polygiene® technology. Made with low concentrations of silver salt, which has anti-microbial properties and is naturally present in water and soil, to safely eliminate the ability for bacteria and fungi to grow. This is only active on the sock itslef and does not interfere with the skins bacterial flora. The added benefit of Polygiene® odour control will not wash out as the technology is bound and permanently integrated into the sock. The Marathon Fresh is also made with LYCRA® SPORT fibre to ensure a close, comfortable fit. Best for: Runners that like a small amount of cushioning, especially in the toe and heel areas for an added touch of comfort. Minimum is the second level of cushioning from HILLY, above our Zero Cushioning level. Features: Polygiene® – permanent odour control Mid-level anatomical cushioning in key pressure zones for optimum comfort Upper foot venting Flat under toe seam construction Materials: 97% Polyamide, 3% Elastane (LYCRA® SPORT)