Re-usable postbags are being used for the shipment of post and letters in which the bags are functioning as cargo-keepers to keep more letters so they can be shipped as one instead of sending the different letters separately. In this way the sender of the letters can save in envelopes and sending costs. The re-usable postbags are made out of a strong material so they can hold the weight and can be used for many years. A zipper closure gives access to the bags and closes them for shipment. To prevent the bag from opening during the transport, specials sealing systems can be implemented. A transparent address holder give the possibility to place an address card with the receivers address in the bag so the courier sees where he has to deliver the bag. All the Krautz postbags are tailor made.