This yarn is wholly imported form England. For socks, I would knit on US#00-0.
The Bluefaced Leicester is of the English Longwool type and originated near Hexham in the county of Northumberland, England during the early 1900's. The Bluefaced Leicester is classified as a longwool breed with a staple length of 3” – 6”, and a fiber diameter of 56’s – 60’s count, or 24-28 microns; creating high quality luster yarns with handle and drape.