Beat the tropical sun. Just put it on.

Yes, they are different. Near-infrared radiation is a type of light contained in sunlight, accounting for approximately 42% of sunlight (compared to about 8% for ultraviolet radiation). It has a longer wavelength than ultraviolet rays and the property of penetrating deep into the skin; it is also known as "aging light" because it raises core body temperature and accelerates skin aging, such as wrinkles and sagging. Therefore, when it comes to preventing heatstroke, cutting out near-infrared radiation is more important than cutting out ultraviolet radiation.

Core body temperature refers to the temperature inside the body, specifically of the brain and internal organs. Heatstroke is a general term for symptoms that occur when this core body temperature rises due to high ambient temperatures or physical activity, and the body's thermoregulatory function can no longer keep up. As core body temperature rises, heatstroke symptoms can worsen and become severe. Depending on the severity of the heatstroke, core body temperatures and symptoms vary as follows. It is also characteristic that while surface body temperature can be lowered with items such as ice, core body temperature cannot be lowered rapidly.

• Mild: 37.5°C to under 38°C; symptoms include physical fatigue, dizziness, headache, and nausea.
• Moderate: 38°C to under 40°C; symptoms include nausea, vomiting, headache, dizziness, weakness, and lightheadedness.
• Severe: 40°C or higher; symptoms include impaired consciousness, convulsions, and difficulty breathing. This condition is also known as heatstroke (sunstroke) and requires immediate cooling.

When the core body temperature exceeds 40°C, organs begin to sustain damage, so it is necessary to lower the core body temperature as quickly as possible.

Yes. The primary factor that raises core body temperature is the accumulation of heat in the torso. This sleeveless design uses a near-infrared cutting material to cover the torso, blocking heat from building up deep within the body. By keeping the arms exposed, it facilitates heat dissipation, making it a design well-suited for dealing with midsummer heat. If you require UV protection for your arms, we recommend the long-sleeve model.

For those who want to focus on sun protection for their arms, we recommend the long-sleeve version, while those who tend to get hot or are looking for an inner layer to wear under a polo shirt should choose the sleeveless style. We also recommend "owning both" so you can switch between them depending on the climate and occasion.

Many people have experienced the effects firsthand, reporting that "the heat feels less intense," "it was comfortable even in direct sunlight," and "the usual fatigue the next day is gone." While the difference in perceived temperature varies from person to person, it is effective in suppressing the rise in core body temperature, so you will especially notice the difference on days with strong sunshine.

While standard sports innerwear primarily focuses on UV protection and moisture-wicking, quick-drying capabilities, this product features a special material that additionally blocks over 76% of near-infrared rays, a leading cause of heatstroke.

Furthermore, it offers approximately twice the drying speed of regular polyester, quickly releasing sweat to reduce the discomfort of the innerwear becoming heavy with moisture.

Distinguishing itself from typical cooling innerwear, this undershirt delivers both superior comfort and functionality.

This product features a stretchable, form-fitting design. If you prefer a looser fit, we recommend choosing one size larger.

• For those with a standard to slightly slim build: We recommend choosing your usual size.
• For those with a solid or fuller build: To ensure a comfortable fit, we recommend choosing one size larger.
• For those with a muscular build or more volume in the upper body due to sports, etc.: For ease of movement and comfort, we recommend wearing one size larger.
  
• For women: When choosing a size, it is safer to use your "width (chest circumference)" rather than your height as a guide.

We accept returns and exchanges even after the package has been opened, provided the item has only been tried on. However, please note that we cannot accept returns or exchanges if the shirt is found to be soiled or damaged.

Because special inorganic components derived from rare metals are kneaded into the fibers, the effect does not diminish even with repeated washing, maintaining stable performance semi-permanently. In addition, it is resistant to wear and aging, offering high durability that withstands long-term use.

※According to tester results: After approximately 50 cycles of wearing and washing, no fraying or pilling of the threads was observed.

Yes, we use an opaque fabric, but if you are concerned about transparency, we recommend the black color.

We use skin-friendly materials, but we cannot guarantee that allergic reactions will not occur in all individuals. If you have any concerns, please consult a doctor or specialist.

UV and near-infrared rays are present all year round; unlike UV rays, near-infrared rays notably do not decrease significantly even in autumn and winter. You can wear this comfortably throughout the seasons: in the warmer months as a measure against heatstroke and sweat, and in the autumn and winter as a way to combat skin aging and cold from perspiration.

Japan is home to many excellent material manufacturers. Unfortunately, however, most products that reach end users—not limited to clothing—are made overseas. We did not want to create products that are manufactured cheaply abroad, consumed in large quantities, and replaced every year. Because our products are designed to protect lives from the threat of heatstroke, we believe that goods carefully crafted with the Japanese mentality are the ones that will truly provide the best long-term value.

We currently also offer hats (bucket hats) equipped with CoreShield. We will continue to expand our product lineup.

Trubeaute® is the name of the special fiber used in CORE SHIELD® fabric. This fiber is embedded with "CWO®" (cesium-doped tungsten oxide), a near-infrared absorbing fine particle developed by Sumitomo Metal Mining Co., Ltd. CWO® is a proven material that strongly blocks near-infrared rays while transmitting visible light, and it is also used in applications such as heat-shielding materials for building windows. Because it is embedded within the fiber, the effect lasts semi-permanently even after repeated washing.

Yes, we accept such requests. We can provide quotes based on quantity and purpose, such as bulk purchases for employee distribution as part of corporate heatstroke prevention measures (in compliance with the amended Ordinance on Industrial Safety and Health effective June 2025), use by sports teams or clubs, and wholesale to retail stores. Please use the dedicated "Corporate Inquiries" form in the header menu to let us know the products you are interested in, the approximate quantity, and the timing. A representative will contact you shortly.