So, to reassure you (or tell you), toner cartridges are compatible with CLP 320/325 printers CLX-3180/3185. Then there is not a single block but 4 cartridges (cyan, magenta, yellow for 1,000 pages for black and 1,500 pages) well separated and well packed in their own cardboard. As you can change cartridges as and when they are used.
Finally, this package is very economical (146.90), while each cartridge sold separately on Amazon costs between 47.90 and 49.90 (for a total ranging from 191 to 199.60) in July 2012. Do the math and do not hesitate.
If the product is indicated with a two days of additional delivery, it is because it comes from England (always in July 2012).