Each yak produces about 100g of fine downy fiber. The average fineness of down from an adult yak is 18-20 microns, while the length is around 30-40 mm. Yaks that live in higher altitudes have finer fiber. The most common natural color of the yak is a dark chocolate brown, but can also be found in white, tan, and grey. Unlike wool, the scales of yak fiber are in a waved mosaic pattern, resulting in a very smooth fiber that does not itch. Fabric made from yak down has more lustre than wool, handles well and provides excellent heat insulation.

The fibres are hand combed from the Yaks that live in these remote areas and who continue to serve as a life source for their Tibetan herders.