You show a beautiful necklace made of "poppit" beads and give it to the audience to be examined. Then ask anyone to call a number. You pull the necklace apart showing a long string of beads and give it to the spectator. Then ask him to pull on the ends of the necklace and the string breaks at the exact chosen number.
-You can repeat the effect with different chosen numbers
-Look like real pearls
-It's always ready
-Can be repeated immediately
-No skill required