Sportztrek Polypropylene Long Sleeve Thermal Shirt is an excellent thermal undershirt, made from one of the softest synthetic fibres available. Polypropylene is a hydrophobic fabric that wicks moisture away from the skin quickly and efficiently, helping to keep you dry and warm. It insulates so well because it has a low thermal conductivity, maintaining your skin as a constant temperature during strenuous activities. This shirt is made in a non-cling style, which helps to avoid post-training chills and aid ease of movement. Particularly lightweight, this garment is ideal if you naturally run warm or are a heavy sweater. An ideal first-layer option, the tough and hard-wearing Sportztrek Polypropylene Thermal Shirt offers maximum performance without sacrificing comfort.