In a mounting device for disk drive, two HDDs are retained in an outer case that forms the mounting device, and an inner case with guiding grooves each including an oblique groove and a parallel groove formed thereon is provided. Polys are prepared via the Michael addition of a bismonomer to a diamine monomer, wherein the diamine monomer has one primary amino group and one secondary amino group, and can be end-capped by reaction with a suitable reagent. The method may further include creating an ETL pyramid having multiple levels, linking the dimension trees to corresponding levels of the ETL pyramid, and creating a table for each level of the ETL pyramid to store a subset of the dimension trees that is linked to a corresponding level of the ETL pyramid. In a measuring bore that forms the forward flow to the side chamber, a rebounding plate of the measuring element is arranged, which is connected by an indicator rod with an indicator of the indicator element.