| Possible match | Explanation | |----------------|-------------| | Canon imageRUNNER 1660i / 1660 II | Uses similar numeric (166) | | Canon imageRUNNER 5000 / 5500 series | “500” suggests high-volume IR series | | Service part number (e.g., FK2-1660-500) | Fxxx numbers often appear on PCBs or fuser assemblies | | Typo: Canon PIXMA MG3660 | But “500” remains unexplained |