This item was purchased to accompany a newly purchased Sony photoprinter. New to the field, one realises that maunufacturers use many different methods to produce colour prints. Some use small cartridges, both singly and in multiple, but Sony have a novel system that includes large rollers and pre-packs of paper combined in a complex single unit. Their method produces a quite bulky 'unit' that clips into the printer rather than being permanently integral. The system is not aesthetically attractive but it does work well and produces prints of very good quality. So, overall, this looks an ungainly system but it does work.
The only downside is cost. To produce 120 6" x 4" prints costs a whopping £28 ($45) or 23-24p (39c) each!! Commercially one can get prints of this size for less than 10p at numerous sites. However on the upside the cost does impose a discipline in being very selective in what you actually print. To be honest I think the product is overpriced but there are no alternatives - just as Sony cameras have their own dedicated non-universal memory stick/card. Its sharp practise in one way but in terms of company profits rather clever. I recommend the product with a price tag warning!