Extra Warm Heattech Cotton Crew Neck T-shirt Long sleeve, cotton inner material, set of 3. The fabric is thick, and the crew neck makes it easy to coordinate and handle. Size: M Colors: Popular white, beige, and navy, which are not see-through and look fine even if visible. The inner side is made of cotton, so it feels good against the skin and doesn't feel scratchy or itchy. Cotton: 53% Acrylic: 42% Polyurethane: 5% Uses a material with ultra-stretch function that fits the body's movements. This is the Extra Warm version from a few years ago, around the time the Extra Warm with 100% cotton inner material was released. I bought them, but I didn't have many opportunities to wear them in Tokyo winters, so I stored them in a garment case. They have been worn only a few times, so there are no pills or fading, and they are in relatively good condition.