Supports up to 2 x 5.25" drives externally, and up to 2 x 3.5" HHDs & 1 x 2.5" SSD internally. A built-in fan bracket at the front supports 2 x 8025mm fans which supplies plentiful airflow for a 2U form factor system. As a miniature sizing of the RM23-502, compatible PSU selection has greater flexibility than the original with support for ATX (PS2), 2U Single or 2U Redundant.