The Jinhao ink cartridges that we sell at Skilltoyz.com fit all Jinhao fountain pens. But inserting the cartridges can be tricky and deserves an explanation.

The end of the ink cartridge has a plastic lug or cap that must be pierced to release the ink.  It can take quite a bit of pressure to correctly insert the cartridge. When you push hard enough, you will hear and feel a click as the plastic end cap is pierced.

For a quick guide to inserting a Jinhao ink cartridge into a Jinhao fountain pen see https://www.youtube.com/watch?v=jxZ0xWtu2cA