Core Shield Men's Long-Sleeve Innerwear, Slim Fit | Near-Infrared Absorbing Fabric, UPF 50+
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Japan's summer hit — 4,000+ sold. Sold on Rakuten, Amazon Japan & Yahoo! Shopping.
⚠ Import duties for international orders: Prices do not include import duty or VAT. Thailand: approx. 1,130 THB (about 46% of the item price) will be collected by Thailand Post on delivery. Malaysia: orders under RM500 are exempt. Australia & New Zealand: no import duty or GST on orders under A$1,000 / NZ$1,000. Ships from Japan by EMS (3–8 days). No returns for change of mind; faulty items replaced or refunded. See shipping policy.
"Trim Fit" will be discontinued once current stock is sold out.
There are no plans for reproduction. Some sizes and colors may already be sold out. Please check stock availability using the size selection below.
View Relaxed Fit (Men's Long-Sleeve Innerwear)
What sunscreen blocks is only
about 5% of sunlight.
The remaining approximately 42% is near-infrared radiation. CORE SHIELD® uses Trubeaute®, a functional fiber that absorbs near-infrared rays while also offering UPF50+ UV protection simultaneously found in sunlight. From the back of your neck to your back and arms, cover up with one piece that requires no reapplication.
Choose the one that suits you from 2 styles
We offer two types of CORE SHIELD® men's long-sleeve innerwear with different shapes but the same functionality. Both feature the same fabric, materials, and sun protection capabilities. The differences lie in the "fit" and "sleeve length." This is the "Trim Fit" type, which follows the contours of your body.
| Item | Trim Fit (Product on this page) | Relaxed Fit |
|---|---|---|
| Fit | Trim fit that naturally contours the body | Soft fit with minimal compression |
| Sleeve Length | Standard length to the wrist | Extra long, reaching the back of the hand |
| Available Sizes | S–XL (for heights 157–178cm) | S–2XL (for heights 162–188cm) |
| Recommended For | Those who prefer a streamlined look/less bulk | Those who prefer a loose fit/hand coverage |
※Sun protection functions (UV protection, near-infrared absorbing fibers, moisture-wicking/quick-drying, and contact cooling) are identical for both types. Trim Fit is preferred by those who want to move actively during golf or outdoor work, while Relaxed Fit is chosen by those who want loose coverage for yard work or daily outings.
Design that meets the "mobility" and "protection needs" of adult men
"The back of my neck burns," "My back shows when I bend over," "The shoulders feel tight when swinging or working," "I get tired wearing it for a long time." Addressing these real-life outdoor discomforts, CORE SHIELD men's innerwear aims to provide sun protection and natural mobility simultaneously.
Mock neck rising toward the back of the head covers the neck
When addressing a golf ball or performing outdoor work, the back of the neck is constantly exposed to sunlight. Our mock neck design rises toward the back of the head, protecting the neck area prone to sunburn.
Longer hem prevents it from coming untucked when bending
Designed with a long hem so your back won't show when bending over. It stays tucked in securely, reducing distraction during play or work.
Stitch pattern designed for range of motion in arms and sides
Considered the movement from the sides to the arms to prevent restriction during swinging, practice swings, or raising your arms, allowing for easy shoulder movement.
3D sleeve design naturally fits the shape of the arm
3D sleeve design that easily adapts to bending, straightening, and twisting motions. Minimizes discomfort during movement for everyone from slim to muscular builds.
Contoured fit that prevents wearing fatigue
Fabric naturally contours to the body without excess bulk. A fit that isn't too tight, maintaining comfort throughout rounds or long hours of outdoor activity.
Sunscreen only addresses about 5% of sunlight
Of the sunlight energy reaching the earth's surface, UV rays account for about 5%. The remaining 42% is near-infrared radiation. Near-infrared rays have longer wavelengths than UV rays and are pointed out to reach deep into the skin.
SPF, PA, and UPF are all indicators for UV rays. There are no items that evaluate infrared radiation. The more time you spend under the sun, the more necessary it becomes to prepare not just for UV rays, but for near-infrared radiation as well.
※Value obtained by integrating the standard sunlight spectrum (AM1.5 global solar radiation/ground surface) according to ASTM G173-03 by wavelength range. Totals may not equal 100% due to rounding.
Trubeaute®: Functional fiber to protect your skin and body
Trubeaute® is a functional material that combines threads infused with special ceramic microparticles, which absorb near-infrared rays, and threads infused with titanium oxide, which reflects UV rays. Because the functional ingredients are infused into the fiber itself, the performance does not easily decline even with repeated washing.
- Near-infrared absorbing thread: Infused with special ceramic microparticles derived from rare metals, which are also used in heat-shielding films for building and car windows.
- UV reflecting thread: Combines threads infused with titanium oxide for UPF 50+ UV protection (tested on fabric alone).
- Infused within the fiber: Because the functional components are inside the fiber, they won't wash away with sweat, and there's no need for reapplication.
Why it's chosen by those who spend time under the sun
Fibers that absorb near-infrared rays
Accounting for about 42% of sunlight reaching the ground, these rays have longer wavelengths than UV and are pointed out to reach deep into the skin. The fabric itself blocks the range that sunscreen and UPF-rated apparel do not cover (tested on fabric alone).
Helps protect against UV rays / UPF 50+
Helps protect against UV rays that affect your skin. Protects your skin during golf, running, fishing, outdoor work, and other scenes exposed to long periods of sunlight (tested on fabric alone).
Wicks sweat quickly and prevents sticking
Approximately double the quick-drying performance compared to common polyester materials. Doesn't get heavy when you sweat, reducing stickiness and clinging.
Contact cooling for comfort from the moment you put it on
A cool touch that is welcome in the hot season. Easy to wear even in sweaty weather, keeping you comfortable even when layering.
Recommended for the following people
For golf, running, and fishing
A round takes about 4–5 hours, with almost no shade on the course. For those who want to focus on their play or hobbies without worrying too much about the sun.
For outdoor work, gardening, and daily outings
Also for long hours of outdoor work, driving, walking, and yard work. An everyday piece for those who spend a long time under the sun.
Made in Japan | We prioritize quality because it touches your skin
Since this innerwear comes into direct contact with your skin, we make no compromises in quality. It is a truly domestic product, with everything from fabric production to sewing and packaging carried out in Japan. We use high-performance sewing machinery also used for swimwear, focusing on mobility, skin feel, and durability.
Product Specifications
Size Chart & Size Selection
Actual Product Size / Height Guide
Unit: cm ※Height is only a rough guide.
| Size | Height Guide (Men) | Length | Width | Sleeve Length | Sleeve Width |
|---|---|---|---|---|---|
| S | 157–163 | 66.5 | 43.5 | 73.5 | 16.0 |
| M | 162–168 | 69.0 | 46.0 | 75.5 | 17.0 |
| L | 167–173 | 71.5 | 48.5 | 77.5 | 18.0 |
| XL | 172–178 | 74.0 | 51.0 | 79.5 | 19.0 |
- Average to slightly slim build: Please choose based on your usual size.
- Sturdier or muscular build: Consider one size up, considering the mobility in the arms and chest.
- Those wearing it for long periods during golf or outdoor work: If you are concerned about feeling constricted, choosing a slightly roomier size will provide peace of mind.
Precautions for Use
- This product is not for medical use.
- This is apparel designed to reduce sun exposure on the skin and body. It is not intended to prevent or treat any medical condition, and it does not guarantee complete protection against sunburn or skin issues.
- This product is apparel and does not prevent or improve age spots, wrinkles, or sagging.
- The relationship between near-infrared rays and photoaging (wrinkles/sagging) is still under research and is not a settled conclusion.
- UPF 50+ is a test result on the fabric itself by a third-party testing agency. Test data on near-infrared rays is currently being measured.
- When active under a scorching sun, in addition to wearing this product, take appropriate heat-protection measures such as frequent hydration, resting, and wearing a hat.
- Please refrain from using a tumble dryer.
- If you feel any abnormality on your skin while wearing, or if it does not suit your skin, please discontinue use.
- Keep away from fire.
- Avoid storing in high-temperature, high-humidity areas or places exposed to direct sunlight.
- Please refrain from using while sleeping.
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