We use unbleached kraft paper which is darker than typical kraft paper.These are window envelopes that are only white on the outside of the envelope (inside the envelopes are dark kraft paper), depending on the ingenuity, you can add a little personality to your shipping bills.These window envelopes are sure to please creators and freelancers.It can also be used for invoice outputs from the "MISOCA" template (window envelope-compatible invoice). Made in Japan at a domestic factory.