The unit comprises of a large reservoir of ink (100mls of each colour) that sit outside your printer. Attached to the reservoir is a set of silicone tubes which feed into special cartridges which you use instead of your current cartridges. The printer works exactly the same way but now you have 100mls of each colour rather than 10mls (which is the contents of the average cartridge).
Even better, when you get low on ink, just pull out the plug on the reservoir and pour in some refill ink.
Best of all you are saving up to 70% compared to the cost of cartridges.
Obviously, the more you print the more you will be saving.
Consider it this way, Brother LC57 cartridges contains 26mls of black ink & 18ml of each colour on average in each cartridge. The Brother Black LC57 cartridge retail for around $42 and the colour cartridge for $25 each ( prices correct as of May 2011 via officeworks online*)
Rihac CISS is prefilled with 400ml of Rihac ink and is equivalant to approximately 19.7 Brother cartridges which would cost you about $575.00 to purchase seperately.