These printers use the 818-6 cartridge:

PitneyBowes-Imagistics 3400

Imagistics 3400

PitneyBowes 3400

Sharp Fax FO-4500

Sharp Fax FO-4550

Sharp Fax FO-5500

Sharp Fax FO-5600

Sharp Fax FO-6500

Sharp FO 4500

Sharp FO 5500

Sharp FO 5600

Sharp FO 6500

Sharp FO 6550

Sharp FO 6600

Sharp FO 6650

Sharp FO 7500

Sharp UX 5000