Cooling ducts direct airflow exactly where a rack-mount server or add-in card needs it: shroud and duct hardware that channels a chassis fan's airflow across a CPU or GPU instead of letting it dissipate through open space inside the case. In a dense rack-mount server, a missing duct is often the reason a component runs hotter than its rated cooling should allow.
Ducts are chassis- and component-specific - order by the exact server model and the CPU or GPU it is ducting, since duct shapes are molded to a particular airflow path and rarely fit a different chassis generation. Reinstall the duct after any internal service; it is easy to leave out during a component swap and the effect on temperatures may not show up until the system is under sustained load. For GPU-dense builds, confirm the duct is rated for the card actually installed, not just the slot it occupies. COLAMCO supplies cooling ducts and airflow hardware for the rack-mount servers business, government, and education data centers run.