Could not find HP910 cartridges anywhere for months. Finally saw a you tube video and thought I would give Ink Products refill kit a try. I was really suprised how easy it was to refill all 4 cartridges. You really need to watch a couple videos and once you see how other people have refilled their cartridges, you are all ready to try it yourself. Took me 45 minutes the first time as I learned what not to do but now takes less than 5 minutes per cartridge. Cleanup takes more time than actual filling and it also is very easy to clean the syringes.