Built around a 22 micron wool / nylon blend, we set out to design the perfect sock. We noticed that the luxurious low-micron socks pilled, shrunk, and generally degraded faster. The marginal increase in softness for a sacrifice in durability didn't make sense to us. Fabric Composition:  52% merino wool, 46% nylon, 2% spandex, 22 Micron, 70 gsm Care & Origin: Machine wash cold, line dry. Made in Korea.