Feeling a little chilly? Wear this vest over your base layer. This is an ultralight and simple vest-style active insulation. It prevents overheating and offers great comfort when in action.

The front uses Polartec Alpha Direct (136g/m2), a highly breathable but warm fabric and the back is the highly breathable, ultralight Shadow Rip*. This is because your back is usually insulated by your backpack.

We recommended pairing it up with our highly air-permeable All-weather series jackets.

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 Shadow Rip; 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 L1096A, 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 1096A (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 Shadow Rip (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.

The mountain environment can be harsh; the weather is often unstable, temperature changes drastically, the wind is strong and the sunlight is intense. In these situations, it is necessary for the outdoor shirt to achieve both a high level of breathability and windproof performance at the same time. Our newly-adopted Teijin’s Shadow Rip fabric is breathable yet windproof while being light and strong.

Usually, thin and light fabrics have a ripstop structure, in which thick yarns are interwoven in a grid pattern in order to enhance tear resistance. This structure, however, often creates an unsmooth surface, causing the pilling due to weak wear resistance.

Shadow Rip is woven with fine, highly strong yarn to achieve a smooth appearance, and offers excellent resistance to snagging and abrasion while being light and strong. It is also wrinkle-proof and pilling-proof, featuring a soft texture.

While the Alpha Vest is lightweight and warm, its structure—where lofted fibers are attached to a mesh fabric—can lead to some fiber shedding over time with wear or washing.

• Use neutral detergent. Machine wash, gentle or delicate at 30°C or lower.
• Wash separately or use a laundry net.
• When the back fabric of this item is wet from perspiration and in contact with white or light-colored wool or silk clothes for a long period of time, the components in perspiration may cause the color transfer.
• Wash to remove the perspiration after use.

　

• Avoid bleach or fabric softener.
• Do not iron. Do not dry clean.
• If necessary, wash to remove the fuzz from the fabric before first use.