This replacement chassis fan, identified by model number ACS-2821-51-FAN, is designed for Cisco 2821 and 2851 routers. It provides reliable airflow to maintain optimal operating temperatures within the router chassis. The fan is engineered to fit the standard chassis mounting points of the 2821/2851 series, ensuring a secure installation. With its proven compatibility, it helps extend the life of the router by preventing overheating. Ideal for maintenance and upgrade scenarios, this fan delivers consistent performance and is a straightforward swap for existing units.