The Alpha Vest, our most minimalist insulation layer, now features a kangaroo pocket made from Shadow Rip. This fabric offers just the right balance of breathability and wind resistance, shielding your core from cold gusts without causing overheating.

The front of the vest uses Polartec Alpha Direct (136g/㎡) to provide warmth and airflow, preventing heat buildup during movement. The back and shoulders are made entirely from lightweight, breathable Shadow Rip to help minimize sweat when wearing a pack.

A minimalist layer for hikers who won’t stop to put on a shell—essential protection in motion.

Key Features

• Polartec Alpha Direct (136g/㎡) for lightweight, breathable insulation
• Shadow Rip fabric on back and pockets for light wind resistance
• Keeps core warm, reducing need for a shell
• Stays warm when wet and dries quickly
• Lightweight and highly packable
• Great as an active layer or minimalist insulation piece

With Polartec Alpha Direct insulation placed only on the front, this vest keeps your core warm while allowing excess heat and moisture to escape. The result is exceptional breathability that helps maintain a comfortable body temperature during high-output activities.

The kangaroo pocket, made from wind-resistant Shadow Rip, adds extra protection at your stomach—shielding you from wind without sacrificing airflow. Thanks to this added defense, you’ll find yourself reaching for your shell less often than with the standard Alpha Vest.

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.

When it’s too warm to justify packing a down jacket, the Alpha Vest Kangaroo offers just enough insulation to sleep comfortably—without the bulk.

The front of the vest features Polartec Alpha Direct, offering an ideal balance of warmth and breathability. In contrast, the back and shoulders use ultra-thin, highly breathable Shadow Rip—with no insulation at all.

Why the difference? When you’re on the move with a pack, your back and shoulders heat up fast. And when you’re sleeping, that same area is pressed against a pad, compressing any insulation and rendering it ineffective. So instead of adding bulk where it won’t help, we focused warmth where it matters most: the front.

When your core gets cold, everything else starts to go downhill. In the worst-case scenario, losing warmth can mean the end of your hike.

That’s why the Alpha Vest Kangaroo includes a wind-resistant Shadow Rip kangaroo pocket—placed exactly where it matters most. It shields your core from biting wind, and you can slip in a tenugui or map for a little extra insulation. Smart. Simple. Effective.

It’s no match for 1000 fill-power down—but the 136g/㎡ Polartec Alpha Direct used in the Alpha Vest Kangaroo is among the warmest active insulation fabrics available. Designed to excel during movement, it also provides enough warmth to serve as a reliable insulation layer during rest stops.

The chart below compares 1000 fill-power down with various insulation materials commonly used in thermal garments.

• 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 surface of the vest, further enhancing overall breathability. It provides warmth without overheating, as excess heat and moisture can escape efficiently—keeping you dry, comfortable, and balanced during activity.

The chart below compares the breathability of various midlayer fabrics.

*Measured by JIS 1096A (Frazier method), in Yamatomichi in-house test.

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.

Like other synthetic insulators, Polartec Alpha Direct resists water absorption and retains its loft even when damp. It stays warm when you’re sweating or caught in light rain, maintaining comfort in variable conditions.

Mountains can be unforgiving—weather changes rapidly, temperatures swing dramatically, winds are strong, and sunlight can be intense. In such conditions, a high-performance outdoor shirt must strike a careful balance between breathability and wind resistance.

That’s why we chose Teijin’s newly developed Shadow Rip: a fabric that offers both breathability and windproofing, while remaining exceptionally lightweight and durable.

Traditionally, lightweight fabrics rely on a ripstop weave—thicker yarns interlaced in a grid to improve tear resistance. While effective, this structure often creates an uneven surface that can cause pilling, especially when the ripstop texture rubs against the skin.

Shadow Rip takes a different approach. It’s woven with fine, high-strength yarns to create a smooth, refined surface that minimizes friction. Despite its soft handfeel, it’s remarkably strong, wrinkle-resistant, and pilling-proof—making it an ideal material for technical garments in demanding conditions.

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.