I bought this sock couple of years ago in San Diego. I don't remember the brand. It has some kind of plastic / polyester feel to it. It slides onto the board easily and kinda water proof. I don't like the cotton ones that I bought in the past because they just soak up all the board water and is a nightmare to put on when the board is still wet.
I know it's not going to be easy as I don't have a picture of the logo or anything.