Behaves like down and doesn't clump
The Thermoball came about 2 years after world-renowned mountaineer Conrad Anker and the rest of the North Face climbing team aborted an attempt to climb Mount Meru in India’s Garhwal Himalaya. It was one of the products designed to help Anker and the team overcome the shortcomings of the last trip and get them through the next attempt.
The Thermoball is soft and comfortable to wear, warm, light, and compact but unlike down jackets, they also keep you warm even when wet.
Thanks to the cotton-ball-shaped synthetic insulation that behaves like down, they cluster like feathers to maintain warmth-retaining air pockets and do not clump together and hinder their ability to keep you warm.
The ability to retain warmth even when wet is common among synthetics but the Thermoball has a weight-to-warmth ratio of about 15% better than the best synthetic insulation. It's warmer, softer, lighter, and more lofty than other synthetics - more like down.
The jacket itself has a durable water-repellent finish,nylon lining that wicks sweat off the skin to help you stay dry and comfortable, and you can stuff it into its own pocket for easy storage.
The Thermoball is a discontinued product from The North Face. The insulation offers warmth equal to 600-fill-power goose down but without the bulk.