You can buy a 13 bead flex bracelet for $1 at dollar store. Buy o rings at hardware store $.30 each. I bought one thin and one thick. Cut the rings to size and glue ends with super glue around bracelet. You count digits with the thin o ring and 10X the other direction with the thick o ring. The bracelet can count up to 39. I placed a gold dot on the insides of both starting beads. In the photo below, it shows the number 16. Six blue beads marked by thin O ring = 6, one dark blue bead with thick O ring = 10. My O rings slip easily on the bracelet.