These printers use the C8061A cartridge:
HP LaserJet 4100
HP LaserJet 4100 D TN
HP LaserJet 4100 MFP
HP LaserJet 4100 N
HP LaserJet 4100 Series
HP LaserJet 4100 TN
HP LaserJet 4101 MFP
TROY-Systems Troy 4100
TROY-Systems Troy 4100 EX