Just like sand paper, except it's black.
Wet or Dry means that it can be used Wet or Dry. As Dave said use it wet, you'll find it easier and you'll get a better result.
EDIT ~ Also known as Silicone Carbide Paper - Silicone Carbide is the abrasive medium as opposed to Sand.
Last edited by Pat.w; 1st December 2008 at 12:04 PM.