The mounting bracket is used to mount either a second HDD or two additional 40 mm fans to the interior of  the M350 Mini-ITX case. Bracket screws into the top of the case.

The case comes standard with one mounting bracket that can either hold one 2.5" notebook HDD or two 40 mm fans. This bracket is only necessary if your application requires two 2.5" notebook HDDs or one 2.5" notebook HDD and extra cooling from case fans.