The synthetic fibers in Supreme Micro Loft material have been developed in cooperation with Fjällräven and are one of the best synthetic fibers that exist today. The combination of thin and slightly thicker silicon-treated microfibers fills the garment or sleeping bag with air, which in turn provides insulation.

The principle is the same as with down padded products. Thanks to an ability to retain their shape even after long-term use, the synthetic fibers are an excellent alternative to down. The synthetic fibers also withstand moisture better and retain their thermal properties even after getting damp.