The rack model can hold 30 tubes and includes locators to which you can point constrain the tubes.
The scene provided is setup with shader materials for mental ray render. The plastic shader material for the tubes can be used for mental ray or maya software render.
Background information on models
The microfuge tube is a standard container in the field of Molecular Biology and is used for mixing, centrifuging, autoclaving, and experimentation. It accomodates the small volumes (1 - 1000 microliter) used in pure and applied research laboratories and forensic labs when working with DNA and other genetic components.
These vials are a commonly seen lab bench item in research labs involved in work on cloning, gene mapping, and forensics.