This Polartec® Power Grid® convertible has been designed to put under a helmet or wear around the neck/face with its superior wicking and fast drying properties. The lightweight grid construction is highly breathable and diffuses next-to-skin moisture vapor for ultimate moisture management. The Power Grid® technology pulls moisture directly from the skin and transfers it to the outer surface to quickly dissipate. This continuous evaporation process helps to keep you cool (as your body heat increases) and warm (when the temperature drops).