u2032 the offsets 800 u2032 allow the bottom 300 u2032 to have the minimal amount of area contacting the sample tube while still providing sufficient support additionally the wells 200 u2032 have support ribs 600 u2032 to frictionally secure the sample tubes in the tray 100 u2032 by minimizing the contact area between the tray 100 u2032 and the sample tubes more surface area of the sample tube is exposed to the sterilizing steam or chemicals of the autoclave as well as the cooling gases or liquids any design that reduces areas where liquids and gases collect increases the overall efficiency of the heating and cooling cycles benefits of the minimized contact area include reduced time for the heating and cooling cycles more uniform flow of liquids and gases around the sample tubes and through the tray and less raw material used in the trays since each sample tube in the tray 100 in the preferred embodiment shown in fig5 is supported by a well bottom 300 the trays 100 may be used in many ways in which the prior art shipping trays cannot be used by the customer or end user the well bottoms 300 prevent the tubes from being pushed upward which is a problem with the prior art shipping or packaging trays this feature allows the free standing trays 100 of the preferred embodiments of the present invention to be used in incubators water baths boilers refrigerators or at laboratory stations additional uses will occur to those skilled in the art the free standing trays 100 are suitable to be used at a laboratory station to facilitate introducing microbial samples into the sample tubes 150.