Mizuno Running Men's Breath Thermo Layered Tights 92% Polyester 8% Spandex Imported Breath Thermo Thermal fabric yarn captures escaping body heat and, through a patented physical reaction in the yarn, generates heat - warming the body Dynamotion Fit patterning is designed to improve fit during sports based on Biomechanical and Anatomical Research, offering freedom of movement WarmaLite Technology recycles escaping body heat, creating an insulating warm lay and keeps the body warm