TWSBI Diamond Mini Clear
TWSBI Diamond Mini Clear Fountain Pen. Transparent crystal-clear diamond-faceted barrel reveals the filling mechanism, a built-in piston-filler with a very smooth action, while also allowing an uninterrupted view of the ink level and color. TWSBI logo nicely finishes the top of the pen's cap. Rubber O-ring on cap thread ensures an airtight seal to prevent ink drying out in the pen, while also ensuring that the cap is firmly attached when not in use.