Cylindrical format:
The cylindrical special format covers Großbrief and Maxibrief letter items falling within the following minimum (L: 100mm, W: 70mm) and maximum dimensions (L: 353mm, W: 250mm, H: 20mm or 50mm). Cylindrical format items may be sent as letter mail if:
- the ratio of the long diameter to the short diameter of an oval cross-section is at least 2:1 (height or thickness = shorter diameter < 50mm) or
- circular diameters can be provided with a firmly attached sleeve of at least 150mm x 150mm
The items may have flat ends like a tube.