Polartec® Alpha® – A Guide

Performance demands control, not just of your pace, but of your body’s microclimate.  Our Polartec® Alpha® series is engineered for precisely that: maintaining warmth and breathability in transitional environments where standard insulation fails. Keeping you confident that your gear won't be a worry whilst you're out and about.

Developed originally for U.S. Special Forces, Polartec® Alpha® is an active insulation, a highly air-permeable thermal fabric that continuously releases excess heat and moisture during activity. Unlike traditional synthetic fills or fleece, Alpha® doesn’t rely on static loft to retain warmth; instead, it regulates dynamically, responding to both movement and ambient conditions.

The structure of Alpha® consists of high-loft fibers connected to a stable mesh core, creating consistent warmth without bulk. This open construction allows air exchange even under shell layers, preventing moisture build-up during exertion while still retaining heat when stationary. The result: dependable thermal control through shifting weather and intensity levels.

Our Alpha® fleeces are designed as versatile mid-layers within a modular layering system. Worn beneath a waterproof shell, they excel in cold, wet conditions where breathability is critical. Worn alone, they provide balanced warmth and comfort in cool, dry environments. Whilst our other Alpha® products use the material with various functions in mind.

Usage Guidance

• High-output activity (hiking, cycling, climbing): Wear the Polartec® Alpha® fleece as a standalone outer layer to manage heat and sweat efficiently.

• Cold, wet conditions: Layer beneath a waterproof shell to retain warmth whilst staying dry.

• Everyday use: The fleece performs just as well on a normal day, making it equally suited for daily wear or travel. Or we'd recommend our Tuba Jacket.

Every detail, from articulated patterning to lightweight hardware, is calibrated for being on the move. Alpha® insulation performs best when kept close to the body, allowing its thermal regulation to operate in sync with your exertion levels.

Built for endurance, balance, and transition, the Polartec® Alpha® range represents PMO’s approach to adaptive performance wear: protection that breathes, warmth that moves.