The Montane Alpha Guide Jacket is a very technical piece of insulation that utilises Polartec Alpha to create a jacket that will add warmth to your set-up but also allows you to work hard while wearing it and you won't overheat or become uncomfortable.
Montane says:
Designed and developed for climbing, the Alpha Guide Jacket gives effective insulation to the core body whilst leaving the arms free from any estriction. It combines the unique properties of PERTEX Microlight Stretch, POLARTEC Alpha and Mt. Thermo X Stretch to create a truly formidable jacket.
The Alpha Guide Jacket provides torso protection in a new and unique way, using the revolutionary POLARTEC Alpha - the latest evolutionary step in synthetic insulation. With its open, woven construction, POLARTEC Alpha combines warmth with hyper breathability, whilst at the same time being extremely compressible. This new format of insulation is encased in PERTEX Microlight Stretch, which provides high wind resistance combined with the stretch needed for climbing movement. The jacket also features a stretch hood that fits underneath a climbing helmet and stretch arms with thumb loops. The Alpha Guide is not so much a piece of clothing, rather a piece of climbing equipment.
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.
Montane have teamed up the Polartec Alpha insulation with zoned areas of stretch fleece - this has created a really interesting jacket that seems to get the best of all worlds insulation wise and is a really useful winter walking layer.
Inside the Polartec Alpha parts are zoned with mesh for maximum breathability.