The carton quality is 450 gsm. The outside is white, the inside is grey. Despite its low pricing, our series of cardboard envelopes offers more than you will expect. You can pack more or thicker products in these envelopes than you will initially think. Thanks to the extra lines and the smart construction, you can easily make a kind of box. Further on, this mail envelope has the well known self-adhesive tape with permanent closing. The receiver can easily and neatly open it with the red tear strip. This prevents your shipment from being opened and closed unauthorized.