Replaces the Following Manufacturer Numbers: HP RG5-2661. Compatible with the Following Printer Models: HP LaserJet 4000N, HP LaserJet 4000SE, HP LaserJet 4000T, HP LaserJet 4000TN, HP LaserJet 4050, HP LaserJet 4050 usb-mac, HP LaserJet 4050N, HP LaserJet 4050SE, HP LaserJet 4050T, HP LaserJet 4050TN.