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- Product Story
- How to
- Form and Function
- Insulated, Just the Front
- Thermal Comparison
- Excellent Air-permeability
- Even Warm When Wet
- Ultralight and Packable
- Polartec Alpha Direct
- Our Proprietary Titanium-coated Pertex Quantum Air
- Titanium-coating Peeling off due to Friction
- Care Instructions
Ultralight, Minimal Active Insulation
Feeling a little chilly? Wear this Vest over your base layer. This is an ultralight and simple vest-style active insulation, suitable when you are on the move.
The front part is made of thick Polartec Alpha Direct (136g/m2), which is thermal and air-permeable, and the back, where your backpack sits, uses breathable Pertex Quantum Air. It prevents overheating and offers great comfort when in action. If it’s chilly when resting, wear a shell over the Vest to keep your core warm. The Vest also boosts the warmth around the abdomen and chest of the body if you sleep wearing it.
The Pertex Quantum Air on the back is treated with a proprietary titanium coating to achieve breathability and lightness while retaining a moderate level of warmth. Combination with the UL All-Weather series jacket, which is also highly air-permeable, is recommended.
Seperation of the titanuim coating
The back of the Alpha Vest is made of titanium-coated Pertex Quantum Air. The titanium coating might peel off with repeated use and washing. In some cases, abrasion spots may be noticeable on the coating caused during the production process.
Please be advised that the seperation of the coating may cause color transfer to your garment worn under the Alpha Vest. For more details, please refer to the “Instructions” section at the bottom of the product page.
Please note the above before making a purchase
Cancellation and Return
If you wish to return the product, even if it has been used, we will accept returns during the below return period.
Please return by Nov. 17th, 2021 (Wed)
For those purchased at Yamatomichi online store.
Please request cancellations through our “CONTACT” page, with “Alpha Vest Return Request” in the subject line (please include your order number in the body of the message). We will return to you with instructions on how to return the product and receive your refund.
Made in Akita, Japan
Front: Polartec Alpha Direct (100% Polyester) 136g/㎡
Back: Pertex Quantum Air (100% Nylon), Titanium Coated 40g/㎡
C6 DWR (Durable Water Repellent)
64g (Size S)
68g (Size M)
74g (Size L)
79g (Size XL)
UNISEX | S / M / L / XL
Akira Natsume, Yamatomichi Founder
Through the development of the Alpha Anorak and the Light Alpha Vest/Jacket, I realized the usefulness of Polartec Alpha Direct as an insulator and was curious to make a lighter and more minimalist product. In the Alpha Haramaki tests, I wrapped the Alpha Direct fabric around my stomach, and it felt great and was warm enough.
How can I create hiking gear that is more simple, versatile, and reasonable in terms of price than a jacket? My answer is our new Alpha Vest.
From the beginning of the development in 2019, we decided to make a vest-style product. The first prototype Vest was entirely made of, including the back, Alpha Direct, but we settled on using it for the front part only. The reasons for this are as follows.
- Enhanced Durability The Polartec Alpha Direct is originally designed to be used in combination with an outer fabric, and fur may come off after repeated friction. Thus, I decided to use the Pertex Quantum Air for the back and shoulders where the backpack constantly comes in contact with.
- Lightness and Packability The back is made of the Pertex Quantum Air for more lightness and packability, making it so small and compact that it fits your pocket.
When I used the Vest in the mountains, I found it useful and comfortable because it was highly air-permeable, preventing heat from building up during activities. If you wear a shell over it, you can block the ventilation and keep your core warm. To be honest, it is not that warm when you stop to rest, and your arms and back may feel cold. But if you’re in the summer mountains, where you don’t need a down jacket, this Vest should be just warm enough. If you are a fastpacker, you can choose to bring only this vest for warm clothes, and use a slightly warmer sleeping bag instead.
Used in combination with our UL All-weather series shells is especially recommended. If the UL All-weather is worn over the Vest, it properly blocks the air to keep you warm.
I feel that the UL All-weather series transmits body heat more smoothly to my sleeping bag than other conventional outerwear, so if the season is right and if you are a minimalist hiker, you may be able to sleep in with the UL All-weather and Alpha Vest.
The Alpha Vest is a novel hiking gear that is minimal, simple, and versatile.
Use When You are on the Move
Use the Vest as warm clothing for chilly weather when you are on the move. The front insulation effectively keeps the chest and abdomen warm, while the outstanding breathability releases heat, keeping you comfortable while in action.
Keeps You Warm When Resting
When resting, wear a shell or shirt over the top. The front Polartec Alpha Direct protects your abdomen and other core parts of the body from getting cold.
Minimalist Warm Clothing for Bedtime
In the summer mountains, the ultralight Alpha Vest works as a backup, warm sleeping clothes instead of an inner down jacket.
Form and Function
Insulated, Just the Front
The front is made of the Polartec Alpha Direct, which has excellent insulation and breathability, while the back and shoulders are made of ultra-thin and highly breathable Pertex Quantum Air; only the front part is insulated. It is because the back and shoulders tend to get hot while on the move when you carry the backpack, and when you are asleep, your back is usually contacted with the sleeping pad and you rarely feel the cold.
Although it is not as warm as 1000 fill power down, the slightly thick Polartec Alpha Direct (136g/m2) used in the Alpha Vest is one of the best insulators available. The Alpha Vest can be used not only in action but also when resting, always keeping you warm.
The below chart compares the 1000 fill power down and other insulators used in thermal clothes on the market.
- Heat retention is measured by JIS L 1096 A method, in Yamatomichi in-house test. The heat insulation property is measured from the amount of energy consumed by the heat-generating element to maintain its temperature. The maximum value is 100%.
- The values of Polartec and Primaloft fabrics are the manufacturers’ catalog specs. Other fabrics’ values are measured by Yamatomichi. 1000 fill power down includes its 7 denier nylon outer and lining.
Highly air-permeable Polartec Alpha Direct is used on the outer fabric, achieving even higher breathability. It is warm but not too warm because heat and moisture can properly escape, always keeping you comfortable.
The below chart compares the breathability of middle layer products*.
*Measured by JIS 1096 A (Frazier method), in Yamatomichi in-house test.
Dries quickly even when wet with sweat.
The below chart compares the fast-drying performance of middle layer products. It is shown that Alpha Direct is not as fast-dry as the extremely fast-drying Pertex Quantum Air (UL Shirt), but the moisture content after spin-dry is much lower than that of wool and other fabrics, and even when wet, it dries quickly if lightly wrung out or worn for some time.
*Tested by Yamatomichi. Compared the difference of the water content after completely wet and 15 minutes of spin-dry. The larger the value, the higher the moisture content, meaning slower-drying.
Even Warm When Wet
The Polartec Alpha Direct, like other synthetic insulators, rarely retains water and its loft is kept bouncy even when wet; It is warm even when you sweat or under the light rain.
Ultralight and Packable
It is lighter than a normal T-shirt, about the size of a 350ml can when folded.
Polartec Alpha Direct
- Excellent air-permeability and thermal performance
- Outstanding lightness and packability
- Polygiene treatment for semi-permanent antibacterial and odor-control
Conventional natural down and synthetic insulators tend to contain body moisture within the clothes and as a result, can be quite stuffy. Polartec Alpha Direct, on the other hand, is so air-permeable that it can be worn even during a high level of physical activity.
Alpha Direct is also treated by Polygiene odor control which safely reduces the microorganisms and bacteria by small amounts of silver ions, achieving antibacterial and deodorizing function that well exceeds the lifespan of ordinary garments.
Polartec Alpha Direct (100% Polyester) 136g/㎡
Bursting strength measured by JIS L 1096 A (In-house test)
Heat retention measured by JIS L 1096 A (In-house test)
Heat retention measured by ASTM F1868 (Catalog spec)
Min : 0.80CLO Max：1.60CLO
Our Proprietary Titanium-coated Pertex Quantum Air
To maximize the superior air-permeability of Polartec Alpha Direct, the shell material of the Alpha Vest uses Pertex Quantum Air, an ultralight and breathable nylon fabric with a durable water repellent (DWR) finish.
The Pertex Quantum Air has many variations in terms of fabric thickness, finish, etc., and we chose one with a matte texture that is pleasant to the skin.
To achieve superior breathability of approximately 70cc/(cm²･s), Pertex Quantum Air is woven as loose as possible, made of less frictional low-count yarns, accelerating the excellent durability against abrasion with coarse materials such as Velcro. Also, the yarn is “temporarily twisted”, twisted and heat-treated to provide moderate stretch for better flexibility.
The back of the fabric is treated with our unique titanium-coating, in which the titanium adheres to the surface of the fabric at the molecular level. The coating enhances heat retention, while preventing body heat from radiating out, without compromising the texture and air-permeability.
Facing: Pertex Quantum Air (100% Nylon), Titanium Coated 40g/㎡
DWR (Durable Water Repellent)
Fracture Strength measured by JIS L 1096 D (In-house test)
Vertical: 0.5kg, Horizontal: 0.6kg
Tensile Strength measured by JIS L 1096 A (In-house test)
Vertical: 29kg, Horizontal: 25.6kg
Ventilation Performance measured by JIS 1096 A (In-house test)
Titanium-coating Peeling off due to Friction
The titanium coating on the back of the Alpha Vest’s Pertex Quantum Air will gradually peel off due to the friction against the back of the base layer, where the weight of your backpack is constantly applied, and eventually be discolored. The discolored fabric can still retain heat as long as the titanium remains in the fabric, but please be advised that when the titanium is completely removed and the base fabric is exposed, the heat retention property is impaired.
The titanium coating on the back of the fabric can gradually wear off due to friction caused by daily washing. The proper care with the right washing method can help maintain the titanium coating.*
*The amount of titanium particles washed away is minimal and considered to be harmless for the environment.
- Use neutral detergent. Machine wash, gentle or delicate at 30°C or lower.
- To avoid damage caused by contact with other laundry, wash separately or use a laundry net.
- Avoid bleach or detergent that contains enzymes as they might discolor the fabric due to the chemical reaction with the metal. Use neutral detergent.
- Do not soak in detergent for a long period of time as it can accelerate the delamination of the titanium coating.
- Wring gently after washing and line dry in the shade.
- Do not machine-dry.
- Do not iron. Do not dry-clean.
- The titanium-coating is meant to be gradually washed away by repeated washing. Wring gently and handle with care.
- The titanium coating may discolor but it does not affect the performance.
- If necessary, wash to remove fuzz from the fabric before first use.
- We only accept payment by credit card. We currently do not accept payment via bank transfer from overseas accounts.
- We accept the following Credit Cards: Visa, Master, American Express, and JCB.
- To download your receipt, please click the link included in the Dispatch Notice, which we will send by email as soon as the items are dispatched.
We will ship by DHL for overseas customers (excluding China, Hong Kong, Taiwan, Korea and Russia). For customers in China, Hong Kong, Taiwan, Korea and Russia, we will ship by EMS only. Shipping costs vary depending on your country and region.
- Overseas customers who need to change the size of their order, should note that the time needed for shipping will vary greatly depending on your country of residence.
- We only accept exchanges when the item is unused (except for fitting).
- If you wish to exchange the size of the item, please contact us within seven days of receiving your order.
- Exchanges can only be made for the same color in a different size.
- If the size you wish is out of stock, we will suggest a different color.
- If the product is out of stock, we may simply have to ship the item back to you.
- All shipping costs to be carried by the customer.
- We will only send the exchanged item to you, upon receipt of return shipping cost via PayPal.
- Please be aware that some countries charge customs duties depending on the price of the item.
- We are unable to answer any questions on local customs. Please contact your local customs bureau.
We accept repairs for all of our Yamatomichi products. For inquiries on repair services including patching the holes, repairing with extra components, or fixing the items damaged over time, please feel free to contact us from the “Repair” section of the SUPPORT page.