The 18-piece set consists of: 00, 11, 22, 33, 44, 55, 6, 7, 8,9 2-end pieces

The 12-piece set consists of: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 2-end pieces.

The number set are interlocking and may be used in combination with letters [only up to 42″, 48″ and up do not interlock]