【Tops (Long Sleeve)】From the moment you fall asleep at night until you wake up refreshed in the morning. What exactly is needed to truly "sleep comfortably"? Wacoal has been researching this for many years and has created "pajamas that are particular about comfortable sleep." That is the Sleep Science brand. Pajama Under (R) is designed to efficiently warm areas that are prone to feeling cold, based on research from the "Wacoal Human Science Research Institute." This long-selling product uses moisture-absorbing and heat-generating materials. The back uses a double-layered fabric for concentrated warmth. This item is carefully crafted using three different materials.