erofa Hongdian Fountain Pen Ink Cartridges Black Color Set, Pack of 30 Ink Refill Cartridges, 3.4 mm Bore Diameter

These cartridges compatible with fountain pen takes 3.4mm cartridges such as Hongdian matte black forest fountain pen How to fill a fountain pen with cartridges: Insert the narrow end of the new cartridge into the black of section block with enough pressure to create a snug fit. The pin inside the section block will puncture the seal of the cartridges, allowing ink to flow into the section block. Screw the barrel on over the cartridge into the section block. Notice: It can take a while for the ink to fully saturate the pen, so don’t worry if it doesn’t start writing right away. You can swing the pen to make a few drops of ink coming out of the nib, so that it can flow easily. When you fill the pen at the first time, you can swing the pen to make a few drops of ink coming out of the nib, so that it can flow easily.