HP 78A Original LaserJet Toner Cartridge Black 2-pack CE278AD. £144 on Amazon.
HP 78A Original LaserJet Toner Cartridge Black 2-pack CE278AD. Comparable with: HP LaserJet P1606 HP LaserJet Pro M1536DNF MFP HP LaserJet Pro P1566 HP LaserJet Pro P1568 HP LaserJet Pro P1606DN HP LaserJet Pro P1606N