TWSBI Obsidian Fountain Pen (Limited Edition) - Mixed black resin with rose gold trim and nibTWSBI Obsidian Fountain Pen A limited edition piston filler with a darker, more architectural presence than anything in the standard TWSBI line. The Obsidian moves away from full transparency and instead introduces a marbled black resin body with rose gold toned accents, creating a pen that feels grounded, refined, and deliberately composed. It still carries TWSBIs engineering focus, but with a more curated, less clinical personality. What sets it