The RK2-0278-000CN is an original HP left‑side cooling fan designed specifically for the LaserJet 4240 printer. This component fits the designated left‑side location and provides the airflow needed to dissipate heat generated during operation, helping to maintain stable printer temperatures and prevent overheating. Constructed to HP’s OEM standards, the fan offers reliable performance and durability, supporting consistent print quality and reducing the risk of thermal‑related downtime. Installation replaces the factory‑installed fan and requires no additional tools or modifications, making it a straightforward upgrade for technicians seeking to restore or enhance the cooling system of a LaserJet 4240.