Product Number: 460407 - Lightweight, while maintaining warmth. - The brushed inner surface is very soft, and the "Ultra Warm" is about 2.25 times* warmer than regular "HEATTECH". *Calculated based on CLO values, which represent the thermal resistance of clothing. Compared to regular "HEATTECH". - Made with a material that combines comfortable functions such as heat retention, moisture absorption and heat generation, moisture absorption and release, and ultra stretch. - Designed with a body width and 10-sleeve length that can be worn as a single layer, like a long-sleeved T-shirt or sweatshirt. - Model Name: HEATTECH ULTRA WARM - Size: M - Material: 41% Acrylic, 37% Polyester, 18% Rayon, 4% Polyurethane