Just checking ebay for Zyx and what caught my eye is that ones coming from Asia (known seller), and selling as new, are not perfectly packaged, missing the outer cellophane bag with a parallel sticker where cartridge model is printed, type is written by hand (manufacturer?) and serial number stamped. Box should have the serial number as the destination country initials. Both Zyx cartridges i have bought from local distributor here in Athens had serial number on cellophane bag, box and typed on manual, and the country initials (GR). Just check ebay to have a better picture. My simple understanding is that refurbished models are travelling around.
G
G