Kaldo is one of the cold, rocky skerry islands around the Gulf of Finland... and also the name of these thick, heavy UpHillSport “Kaldo” Hunting H5 Boot Socks, inspired by the often-sub-zero conditions of the wet, icy windy environment. These thermal grade 5, merino wool-rich hunting and fishing socks keep the cold at bay while breathing out unwanted moisture from the inner. The calf height sock shaft has a half-ribbed 4 x 1 knit, while the foot incorporates a comfortable, insulating terry loop cushioned half foot, and has a fitted heel which assists in keeping the sock in place, wrinkle free. All UphillSport socks incorporating merino wool come from mulesing free farming sources.