This is a perfect low cost/ high quality DIY chassis for big projects, if you are using amp modules that have already the PCB mounted onto the heatsinks. Internal volume for 4U- 300mm/400mm depth is so big, that you could build a 5+1 amplifier inside easily by using ready heat-sinked modules. I was using it to re-box an Anthem 225 amplifier, and all the elements has space to cool inside. I was using the spare top
'HIFI 2000 Perforated housing cover 19 "300mm' to allow air circulation.
As the box cannot bear a massive weight on it's own in basic version, my advise is to use this spare bottom: 'HIFI 2000 Inner baseplate 425x260mm (300mm Series)', or to reinforce the chassis base with some L aluminum profiles. It was not my case, as the bottom was reinforced by the 2 massive heat-sinks of Anthem modules. The finish of the 4mm face plate is top notch! Also, the black matte anti-scratch paint of the top/bottom covers is of good quality. The bottom and back-plate steel is easy to process (drilling, milling), as the material does not have a high hardness. Despite the chassis seems to flex without the top cover mounted, when assembled, the whole structure become rock solid! My project weights about 15 Kg, and the box is like a rock-stone once assembled. Highly recommended for tight budget projects.