This is Uniqlo's Heattech, the thinnest regular type. I wore it for one season last year, but it's still in good condition with no noticeable stains or pilling, and is still wearable. - Size: M - Material: 33% Polyester, 31% Acrylic, 21% Rayon, 15% Polyurethane #Uniqlo #Heattech #Innerwear #Underwear Thank you for looking.