F166400 (also written as F-166400)
Here is the complete identification and specification for this part number:
Approximately 50,000 to 80,000 pages (depending on media type and coverage).
If you need the or step-by-step replacement instructions for this specific fuser, let me know.
Canon OEM F166400 is expensive. Third-party / compatible fuser units are available, but quality and longevity vary significantly.
Fixing Assembly (Fuser Unit)