Troy Black MICR Secure Toner Cartridge for Troy & HP M501, M506 (02-81675-001)
HP LaserJet Enterprise M506 Toner Cartridge - Clickinks.com
Amazon.com: MICR Toner International Compatible Magnetic Ink Cartridge Replacement for HP 87A CF287A LaserJet Pro M501 Enterprise M506 MFP M527 Printers : Office Products