Polypropylene is not a dyed fabric. The color is built into the fabric so you won't have any bleeding or fading. Polypro keeps feet warm and dry. Polypropylene is a synthetic fabric that does not absorb any water making it hydrophobic. The fabric speads water evenly across the feet allowing the fabric to dry quickly.
*The Black sock is manufactured for the military. It says it fits mens sizes 10-13, but it will easily fit down to a Men' size 8.