Bionic base layers are constructed from SPORTWOOL, a unique fabric that blends the best properties of both Merino wool on the inside of the fabric and polyester on the outside. Merino wool excels at trapping moisture vapour perspiring from the skin whilst polyester transports that moisture in liquid form and spreads it out enabling the garment to dry extremely fast. This unique composite construction and performance results in the wearer: 1. Feeling cooler during exercise resulting in the delay of sweat creation. 2. Liquid sweat is transported to the outside of the garment more quickly result in no clamminess. 3. Wearer stays cooler during exercise. 4. Post exercise chill is reduced.
From my experience this is by far and away the best base layer I have ever used walking and mountain biking. Fabric: SPORTWOOL Grid