Model Compatibility: Compatible with Canon IR 6000, IR 5075, and IR 5050 series multifunction devices, providing duplex printing functionality to these models. Function: The Duplex Unit RC facilitates automatic two-sided printing, which helps to save paper and reduce overall printing costs. It works by feeding the paper through the printer, printing on one side, then reversing the paper and printing on the other side. The "RC" in the name refers to the Reverse-Cycle mechanism, which means the unit uses an efficient cycle to reverse and refeed the paper for double-sided printing.