4 PCS Tip Adapter for refilling 950/951 and 932/933 Cartridges | Can be put in front of regular syringes for tool-free easy refill. Tip OD = 2.8 mm; Tip Length: 9 mm; Base ID = 4 mm; Base Length: 10 mm. | Find the ink outlet hole (see picture), insert the tip all the way into the hole | Inject ink and then release the syringe. Wait till the air fill up the syringe and pull syringe out. | It can fill cartridges many times untill the printer prevents further usage, or you can install a permanent BCH950ARC4 chip (B00UNI03F6) and refill the cartridge forever.