Sonnenleder pen case "Karasek" mocha brown

The Sonnenleder pen case "Karasek" in mocha brown is a leather case handcrafted in pure leather work for two writing instruments. The leather comes from South German cattle and is tanned purely vegetally in the pit – a process that gives the material its open-pore, lively surface and characteristic warm leather scent. The shaping is created through water hardening: the leather is soaked in water and dried on wooden forms, which allows it to permanently retain its compact, protective shape.

Special Features

• Pit tanning with vegetable tannins: The leather is tanned purely vegetally without synthetic chemicals. The result is a breathable, open-pore material with natural tactile quality – warm and slightly rough to the touch, never smooth-synthetic.
• Water hardening for permanent form stability: Soaking and drying on wooden forms gives the case its firm, self-supporting structure. Fountain pens, rollerballs, or pencils sit securely without the case deforming.
• Two separate compartments: Each writing instrument lies individually in its own leather compartment – no scratches from direct contact, no slipping. Suitable for writing instruments up to approximately 14.5 cm in length.
• Slot flap as closure: Without zipper, without snap button – the simple slot flap keeps the case securely closed and can be opened with one hand.
• Mocha brown: Warm, earthy brown tone with slightly uneven surface texture – every natural grain and structure remains visible and tangible in the finished piece.
• Living patina through use: Rain, heat, and sunlight change the leather's color tone over time. Each specimen develops its own distinctive appearance.
• Pure handcraftsmanship, Made in Germany: Every piece is individually handmade. Minimal variations in color and surface structure are not defects but evidence of the authenticity of the material.

Application & Tips

• The case accommodates writing instruments up to approximately 14.5 cm – this fits most standard fountain pens (e.g., TWSBI Eco, Kaweco Sport with cap), rollerballs, and standard-format pencils.
• Longer fountain pens with attached cap (e.g., TWSBI 580 or 700R) exceed 14.5 cm. In these cases, it is advisable to remove the cap or use a smaller writing instrument.
• Fresh from hand, the leather is slightly stiff – this subsides after the first weeks of use. A thin application of natural leather fat or balm keeps the surface supple and protects against drying out.
• For your bag, desk, or as a travel companion: The case protects delicate pen nibs from mechanical pressure from other items in your bag or backpack.
• Moisture stains from rain are not damage – vegetally tanned leather absorbs water and releases it again without cracking. The stain often fades completely when drying or becomes part of the developing patina.

For Leather Enthusiasts

Pit tanning – bark and hides together in a water-filled pit bath – is one of the oldest tanning methods of all and is practiced today by only a few tanneries. The process produces leather with an open pore structure: the surface is not sealed, meaning that moisture is absorbed and released again. This property is precisely what makes the leather so reactive to environmental influences – and explains why the patina progresses differently on each piece. The mocha brown of the Karasek case is dyed through the vat; however, the base color of the grain remains slightly irregular because the natural fiber structure of the leather absorbs the dye differently. This is not a quality defect, but the hallmark of genuine, unfinished natural leather.

Technical Specifications