Polartec High Loft is a lightweight, airy fleece with a tall, lofted pile that traps a lot of warm air for excellent warmth-for-weight, while compressing small and staying breathable. Often used as a 'fleece insulation' alternative to a puffy, it gives cozy, low-weight warmth for mid layers, blending the breathability of fleece with loft closer to that of insulation.
Polartec Power Grid is a lightweight fleece with a distinctive grid pattern knitted into its inner face, which reduces weight and boosts breathability while the raised grid traps warmth and channels moisture. Highly versatile, it's a favorite light mid-layer and cool-weather base layer for active use, balancing warmth, breathability, low weight, and quick drying.
Polartec Thermal Pro is a family of warm, breathable technical fleeces, often with high-loft or textured constructions that trap more air for greater warmth-for-weight than basic fleece. Durable and quick-drying, it's a popular mid-layer fabric for cold-weather warmth that still breathes, spanning everything from smooth fleeces to fuzzy high-loft 'sweater' and grid styles.
Polartec Alpha is a breathable 'active insulation' originally developed for U.S. Special Forces, designed to insulate while letting heat and moisture escape during exertion. Its lofted, air-permeable structure (often sandwiched between breathable face fabrics) makes it ideal for high-output, stop-and-go activities where a traditional puffy would cause overheating.
Polartec is a brand of technical performance fabrics best known for pioneering modern synthetic fleece, which insulates while staying breathable, quick-drying, and warm when wet. Its broad range spans lightweight grid fleece (Power Grid), warm high-loft fleece (Thermal Pro), active insulation (Alpha), stretch fabrics (Power Stretch), and waterproof-breathable membranes.
Active insulation is a category of highly breathable insulation designed to be worn while moving, venting excess heat and moisture during high effort instead of trapping it like traditional 'static' insulation. It keeps you comfortable across stop-and-go aerobic activity, reducing the need to constantly add and remove layers. Examples include Polartec Alpha and Octa-based fabrics.
Thinsulate is 3M's brand of thin, lightweight synthetic insulation made from very fine microfibers that trap air in a small space, delivering warmth without much bulk. It retains warmth when damp and is widely used where slimness matters — gloves, hats, boots, and casual winter jackets — rated by gram weight (e.g., 100g, 200g) for warmth.
Octa is a lightweight Japanese insulating yarn with a hollow core and eight fin-like projections that trap air to create warmth at very low weight, while remaining highly breathable. Knitted into lofted, airy fabrics, it's used in active insulation and grid-style mid layers prized for being exceptionally light, quick-drying, and breathable for high-output use.
PrimaLoft Cross Core is an insulation technology that infuses PrimaLoft microfibers with aerogel — one of the world's best-insulating, lightest solid materials — to boost warmth without adding thickness or weight. Used in PrimaLoft Gold products, it delivers more warmth for the same loft, helping make slim, low-bulk yet very warm insulated garments.
PrimaLoft Gold is the premium tier of PrimaLoft synthetic insulation, offering the brand's best warmth-for-weight, compressibility, and water resistance using its finest microfibers. Available in versions for static warmth and active breathability — and with technologies like Cross Core (aerogel) — it's used in high-end jackets and sleeping bags seeking near-down performance that still works when wet.