Polartec Thermal Pro was developed to bring a wider range of styles and performance functionality to synthetic fleece technologies. By re-engineering their construction methods, they created an expansive platform of fabric structures with superior benefits over traditional fleece. These unique textures enhance the fabric's overall efficiency and are the defining reason why synthetic fleece will never go out of style as the preferred choice for performance insulation fabrics. Thermal Pro Technical Sweatshirt is a unique fabric. The face is a smooth heather jersey while the back is a microfleece grid. This fabric has very little stretch so consider sizing up or using with patterns that call for a low stretch percentage.