Return Program toner cartridge is essential to Lexmark print system performance and designed for use in Lexmark CX310dn, CX310n, CX410de, CX410e, CX410dte, CX510de, CX510dhe and CX510dthe. Unison Toner's unique formulation consistently delivers outstanding image quality, ensures long-life print system reliability and promotes superior sustainability - all in an innovative, shake-free print system. Standard yield of approximately 1,000 pages is perfect for low-volume printing. Lexmark Return Program cartridges are patented print cartridges sold at a discount in exchange for the customer's agreement to the license requirement that the cartridges will be used only once and returned only to Lexmark for remanufacturing or recycling. These patented cartridges are licensed for single use only and will stop working after delivering a fixed amount of ink and/or toner. Ink and/or toner may remain in the cartridge when replacement is required.