"The Patagonia R1 Pant is a Polartec Power Grid fleece bottom built for ski touring, hiking, and camp. The grid-knit construction does two things at once: the raised fleece squares trap warm air against the skin while the open channels between them move moisture away under load. What Our Gearhead® Experts Are Saying:""I wear these under shell pants on cold ski days and pull them on around camp when the temperature drops. The grid fleece holds warmth when I stop moving but doesn't overheat me on the skin track."""