Slim duct units are hidden air handlers that connect to short runs of ductwork to cool one or more rooms discreetly. You can find these in our Slim Duct Multi-Zone collection. The MRCOOL Olympus Duct 24,000 BTU is a powerful hidden solution. They are often installed in attics or above closets where they are completely out of sight. This allows for the use of custom grilles that match your interior design. It combines the benefits of ductless efficiency with the aesthetics of central air.