Riso S-539E 2X1000ML Refill KIT Inkjet Cartridge, Refill Kit

The ink cartridges are superior, arrived on time. Silly me, I did not at once see where the guide arrow is for inserting into the machine, but when I looked carefully, it was clearly displayed - just my haste that caused a minor frustration.

THe ink worked just as it should have with the model of risograph that we have. I would recommend it.