C5 is a small form factor ATX case based on the idea of functional integrity of the product. It is an ATX case iteratively derived from MATX C3 PLUS. The shell is made of l.5MM aluminum-magnesium alloy. In terms of structural strength, the main structural strength is enhanced by L-shaped crossed buckles design and multiple bending processes. In terms of product functionality, it is design with wire management at back, bottom independent PSU cabinet and front side cooling channel. In such a small space it supports 5 HDD with longer video card support, and many other iterative optimization makes C5 a perfect integral product. Even ordinary users can easily build a small-sized ATX system with clear wiring and unobstructed heat dissipation.