37.5® Technology is dynamic as it works with your body to determine if you need warming or cooling based on the amount of humidity next to your skin. 37.5 particles capture the infrared (IR) energy your body emits and speeds up the evaporation process to cool the wearer. If no moisture is present, the IR energy is returned to provide warmth.
37.5® Technology is developed with active particles that naturally occur in volcanic minerals. Embedding these into fibres and yarns produces a highly durable product with no loss of active-particle concentration over time. 37.5® Technology fabrics carry the OEKO-TEX® Standard 100 certifications of 37.5 polyester staple fibre and filament yarns.