FIG. 5A is a side view of alternative latch mechanism 216 of the PCI cassette 202 in a closed configuration. FIG. 5B is a side view of alternative latch mechanism 216 of the PCI cassette in the closed configuration showing elastic deformation (exaggerated for clarity) of primary spring 218 and secondary spring 238. In the illustrated embodiment, latch mechanism 216 is similar to latch mechanism 116 (shown in FIG. 2A) except that primary spring 218 is integral to latch 222. Thereby, the same reference numerals will be used for latch mechanism 216 where the corresponding components are the same as in latch mechanism 116. However, reference numerals that are one hundred higher are used for components of latch mechanism 216 that are different from those in latch mechanism 116. FIGS. 5A and 5B will now be discussed in conjunction with one another.