This is a BISONTEC refill kit to replenish the ink in our BISONTEC Continuous Ink System. This refill kit is equivalent to 8-10 cartridges PER COLOR! Thats a total of about 40-45 cartridge yields all in this 1 refill kit! If you had to buy each cartridge separately you could spend over $600 for original cartridge brands or over $300 for compatible cartridge brands. This BISONTEC refill kit is the perfect buy for high volume printers at less than $50 this represents over 90% savings compared to buying new OEM cartridges! Easy to use.