The KL04 has a unique 5cm spacing designed between the drive cage and the intake fan, which enables cool air to flow directly onto
installed hard drive’s aluminum surface. This design has been validated by SilverStone’s R&D team through repeated thermal testing
to be fully capable in coping with fully installed cage.
The extra 5cm spacing also allows KL04’s graphics card cooling to be unaffected by the number of hard drives installed.
The extra space there is designed for cable storage. If you are using a
non-modular power supply, you can store extra cables there. Even if you
use modular power supply, you can still store unused cables in the extra
space to avoid misplacing them.