These printers use the C6615 cartridge:

HP Color Copier 310
HP DeskJet 810 C
HP DeskJet 812 C
HP DeskJet 816 C
HP DeskJet 825 C
HP DeskJet 825 CVR
HP DeskJet 840 C
HP DeskJet 841 C
HP DeskJet 842 C
HP DeskJet 843 C
HP DeskJet 843 CXE
HP DeskJet 845 C
HP DeskJet 845 CVR
HP DeskJet 916 C
HP DeskJet 920 C
HP DeskJet 920 CVR
HP DeskJet 920 CXI
HP DeskJet 940 C
HP DeskJet 940 CVR
HP DeskJet 940 CW
HP DeskJet 940 CXI
HP DeskJet 948 C
HP DeskJet 3810
HP DeskJet 3816
HP DeskJet 3820
HP DeskJet 3820 V
HP DeskJet 3820 W
HP DeskJet 3822
HP Digital Copier 310
HP Digital Copier Printer 310
HP FAX 1230
HP FAX 1230 XI
HP OfficeJet 5105
HP OfficeJet 5110
HP OfficeJet 5110 A21
HP OfficeJet 5110 V
HP OfficeJet 5110 XI
HP OfficeJet V-30
HP OfficeJet V-40
HP OfficeJet V-40 XI
HP OfficeJet V-45
HP OfficeJet V
HP Printer Scanner Copier 500
HP Printer Scanner Copier 500 XI
HP Printer Scanner Copier 720
HP Printer Scanner Copier 750
HP Printer Scanner Copier 750 All In One
HP Printer Scanner Copier 750 XI
HP Printer Scanner Copier 750 XI All In One
HP Printer Scanner Copier 760
HP Printer Scanner Copier 920
HP Printer Scanner Copier 950
HP Printer Scanner Copier 950 All In One
HP Printer Scanner Copier 950 VR
HP Printer Scanner Copier 950 VR All In One
HP Printer Scanner Copier 950 XI
HP Printer Scanner Copier 950 XI All In One