The dotted lines seen in the OL179 are back slits in the liner of the material, rather than perforations in the material itself. This particular option is popular for applications where you are manually cutting into the material and need the backslits to facilitate easier removal of the label from the liner. Please reach out to our Customer Service Team directly so that we may better assist you with finding the perfect label for your needs. https://www.onlinelabels.com/Support/SupportRequest.aspx