Woolpower. They are merino synthetic blends for extra durability. Merino and durable don't go together. They make everything out of a factory in sweden. For quality control, a complete piece of clothing is sewed by 1 person and has that makers tag on it, as opposed to the assembly line style.

Their sweat fabrics are very close knitted which makes them really wind resistant for a sweater, but it's easy to get snagged on branches.