Marmot's Isotherm 1/2 Zip Top uses Polartec Alpha synthetic insulation to provide lightweight warmth with high levels of breathability.
Marmot says: The same active insulation in the Isotherm Hoody, the Isotherm ½ Zip is ideal for active use in cold environments. Its 20-denier Pertex Quantum® fabric is filled with a hyper breathable Polartec® Alpha® insulation — the latest and greatest in breathable warmth. This lightweight layer has a zonal mesh lining, free-movement underarm design and elastic drawcord hem. Comes with a zippered chest pocket.
||||Polartec Alpha, Overheating is Underperforming - So unlike traditional synthetic fill or down, Polartec Alpha allows a free exchange of air to keep you warm, comfortable and focused. Developed for U.S. Special Operations and now available for outdoor enthusiasts, it takes performance fabric—and you—to a totally new place. Click the Logo to read more...|
||||Pertex Quantum Fabric - Light enough to enable down to loft better, comfortable enough for next-to-skin. Click Logo to read more...|
Marmot's Isotherm 1/2 Zip Top uses Polartec Alpha synthetic insulation to provide lightweight warmth with high levels of breathability. Designed to be worn when you are active - so on the move - there are alternative insulation garments that are more suited to wearing around camp - Polartec Alpha is about keeping you vented even though you are also being kept insulated.
Its quite a breakthrough, especially for cold weather walking when you need insulation but start sweating hard when you reach a strenuous bit. Weight for weight Polartec Alpha is only about half as warm as Primaloft so the king of insulation keeps its crown - but Alpha has its place - I recently wore an Alpha garment all day while walking in Corsica in particularly cold conditions and stayed warm & comfortable for the duration - I kept checking my baselayer, which stayed completely dry.
The Isotherm 1/2 Zip Top supports the performance of Alpha with zoned mesh areas in sdie the garment to enable the high levels of breathability attained by the insulation. It has stretch cuffs and a drawcorded hem. Large-ish chest pocket.
- Reviewed by Ultralight Outdoor Gear