What distance should the pens be apart when I write?

• If you have purchased a second optional interactive pen, the two pens should be used at least 4 inches (10 cm) apart from each other when writing to prevent the pens from interfering with each other.

  Note: Writing with the two pens closer than 4 inches (10 cm) apart may result in skipping and broken lines.

  Related references
  Optional Equipment and Replacement Parts