The TWSBI Diamond Mini Fountain Pen in Clear features a transparent, diamond-faceted barrel that showcases the internal piston-filling mechanism and ink level. It is equipped with chromed metal trim, a pocket clip, and a rubber o-ring on the cap thread for an airtight seal. The pen's barrel is threaded for secure cap posting. It has a polished steel nib, available in various sizes including fine, medium, broad, extra-fine, stub 1.1mm, and stub 1.5mm. The pen measures 117mm long closed, 108mm long open, and 140mm long posted, with a maximum barrel diameter of 12.4mm and a grip section tapering to 9.8mm. It weighs 18g. Please note that piston-filler pens cannot use cartridges. The pen is supplied gift-boxed and can be entirely disassembled for cleaning and servicing, with instructions and tools included. Disassembly is recommended for experienced users and is at your own risk.