IT can be used to grind Salt or Pepper. In order to keep track of what you’re grinding, there’s a little round magnetic disk recessed in the top of the mill. One side of the disk is engraved with an S and the other side with a P.
You can easily flip the disk from one side to the other based upon what you’re grinding. That really helps if you buy the set. It’s also helpful if you want to play jokes on your kids by flipping the top to S when there is pepper inside.