DS416slim NAS from Synology or the baby-NAS as we’d like to call it is incredibly compact for a 4-bay unit (even if we are discussing about 2.5’’ drives), is incorporating an active cooling system, while the back trays can be installed or removed in a snap. The fan can be easy removed for cleaning or replacement and the manufacturer did not omit to include extra USB 3.0 ports for expansion, both in the front and back.