Custom 823 Transparent Fountain Pen

Pilot Custom 823 Demonstrator

The Pilot Custom 823 stands out with its distinctive vacuum filling system.
It comes in two transparent color options: Demonstrator Brown and Dark Grey.
The pump mechanism, shown above at half-stroke, generates a vacuum on the downstroke, which releases as the piston moves past a broader section of the barrel near the grip, allowing ink to be drawn into the chamber.

Additionally, the ink supply can be sealed by tightening the plunger. To enable writing, simply twist the end cap about 2mm to open the ink flow.