This combo pack includes three pairs of simply designed socks made of undyed organic cotton. The leg of each sock is 1x1 rib knitted for soft stretch, while the foot is jersey knitted for less stretch to avoid the item to be crumpled in leather shoes. Knitted with naturally colored cotton (Chamen), the brown pairs are undyed, let alone the ecru one. The gray color is created also not by dyeing but by causing a chemical reaction on rare pale green cotton (Midorimen), while applying a plant dying method called mordanting to fix the color. The color was born as a by-product of a study to prevent Midorimen cotton from color fading by sunlight because the material inherently has low color fastness to light.