Made in Japan on vintage knitting machines using merino wool and organic cotton. These double face socks have been in ROTOTOs collection since the establishment of the brand. Designed with an inspiration from mountaineering socks, these socks feature merino wool on the surface, which helps heat retention, and undyed low-count organic fleece pile cotton fabric as the lining, to create a soft and thick feel like a sweatshirt. The liner material feels fluffy and comfortable with a napped surface. These are great for knocking around the house in but also good for a long hike. Seriously good socks and a best seller every season. Details: Marled finish, Fleece back lining, Extra soft hand feel, Merino wool / Organic cotton / Polyester and Polyurethane, Made in Japan. Style R1001. Size Chart: Size M L Approx. UK Shoe Size 7-9 10-12