... to fill a writing case like this one: six Monolith graphite pencils (all gradations), a Koh-i-Noor lead holder with twelve spare graphite leads (Ø 2 mm), a Granate pencil sharpener with three spare blades, a small triangular ruler (15 cm and 6 inch scale) made of untreated maple wood, an eraser, a pencil extender and a pencil cap. The case is made of hand-flattering pit-tanned Allgäu cowhide and is carefully stitched and will take on an individual patina with time and use.

Sonnenleder in Bodman-Ludwigshafen on Lake Constance stands for a consistently functional, pure design. The meticulously working company still uses the traditional method of leather production: vegetable pit tanning. Only hides from southern German cattle are used for this. The tanning agents used contain mainly decoctions of bark, roots and fruit. In twelve pits with slightly increasing concentrations of tanning broth, they convert the protein fibers of the cattle hides into leather fibers over a period of six to twelve weeks.
After tanning, the hides are air-dried and greased in a lubrication barrel according to a well-guarded recipe. Undyed, the finished leather has a characteristic, slightly light brown-reddish hue, which also gave the leather the name "red-tanned" and which varies from batch to batch. Use, sun and rain change the color tone, and over time a natural protection forms, the patina, which gives the leather an unmistakable appearance. The leather dyed in the barrel also acquires a shiny patina with use.