SmartWool PhD NTS Light 195 Wind Zip Top 1CFM Windproof - This garment is windproof with a 1CFM rating, to keep you securely comfortable, ensuring the elements don't disrupt your training. Thermoregulation Properties - The merino wool fabric helps to regulate body temperature, due to its natural moisture-management and thermoregulation properties. The regulation of body temperature also helps to lower heart rate and prevent the production of lactic acid which leads to cramps, as blood can flow more freely as the body begins to cool. Interior Flatlock Seams - Provides additional comfort and helps to prevent the risk of chafing. Sculpted Side Panels - Reduces chafing and provides a body-enhancing, slim fit for extra comfort. 13" (33cm) Centre Front Zip - The front zip provides extra ventilation when needed and enables the top to be put on and taken off with ease.