There are a lot of other similar socks being sold on Amazon. However, the quality can really vary. Look for the trademark on the sock to ensure that you are getting the real Copper Sole sock. Below is a picture that shows the trademark on the cuff of the sock.
Update: I have had these for almost a month know and have worn them to work and for hiking. They have held up well to multi washings and wearing them with different types of shoes and/or boots. I am really impressed with the quality of these socks.