The Schneider SN166101 piston converter allows you to use bottled ink in your fountain pen with complete cleanliness and ease. Made of highly durable transparent acrylic with a helical piston mechanism and international standard connector, it replaces traditional disposable cartridges. The transparent body allows you to instantly see the amount of ink remaining in the reservoir. It is the ecological and economical choice for calligraphy enthusiasts who prefer to refill fountain pens with bottled ink.