For plant labels. You write on them heavily with ball point pen and as the copper weathers and the ink washes away the indentation becomes more distinct and is easily read. Well, that is what is supposed to happen. I don't think I leaned heavily enough on it when I wrote so the writing has completely disappeared and now it is just a pretty decoration. I shall have to try again. I seem to remember all my folder paper curling up on itself when covered on both sides with my heavy handwriting when I was studying for the HSC. I must be losing hand strength as I age. Sigh.