The Developer Unit Compatible With C6500/C6501 Empty Refurbished that you are considering includes a refurbished developer unit that has been thoroughly inspected and cleaned, ensuring optimal performance. Unlike new units, however, this one does not come with the necessary developer powder, a necessary component for the proper functioning of the device. This is because developer powder has a limited shelf life and is prone to degradation over time, making it essential to replace it periodically. By opting for an empty refurbished developer unit, you are not only enjoying cost savings but also ensuring the longevity and reliability of your machine.