This is a replacement caddy for the HDD trays for the NZXT H2 case.
It can be used to mount 3.5'' HDDs or 2.5'' HDDs or SSDs. Unlike the original, this design uses bolts to secure the HDDs/SSDs. It has an additional screw hole on the side to be locked into place in the case.

Unlike the original part, my version hooks into the retainers on the top, which makes it easier to print as a single piece. This however means that it won't work in the uppermost caddy position. The small vertical pillars within the spring-loaded parts in the walls are meant as support, but if they cause the springiness of the springs to be too stiff, they can easily be snipped with a wire cutter.