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.

Made in Akita, Japan

Material:
Front: Polartec Alpha Direct (100% Polyester) 136g/㎡
Back: Pertex Quantum Air (100% Nylon), Titanium Coated 40g/㎡
C6 DWR (Durable Water Repellent)
Weight:
64g (Size S)
68g (Size M)
74g (Size L)
79g (Size XL)
Size:
UNISEX | S / M / L / XL

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.

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.

In the summer mountains, the ultralight Alpha Vest works as a backup, warm sleeping clothes instead of an inner down jacket.

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.

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.

It is lighter than a normal T-shirt, about the size of a 350ml can when folded.

• 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.

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.

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.