Before there was indigo, there was woad. Dyers all over Asia and Europe mashed and fermented Isatis tinctoria to make their fabrics blue from the Stone Age through the 1600s, when it was largely replaced by the Indigofera plant. Synthetics have since made them both obsolete, but some brands still make things the old fashioned way.

One of the biggest proponents of natural woad dyeing is the UK’s Tender Co, as seen on this pair of socks. They’re tube knit with a double terry cloth sole, hand-appliqued letter, and of course, dyed in natural woad. The process is incredibly labor intensive and there’s only a small amount of the plant still grown for dye purposes, so this pair of cotton-nylon socks comes in at a whopping $40, but hey, you don’t have to worry about crocking on them from your jeans!

You can find them now at Hickoree’s.