Hi Definitions:

Some of the commercial cage and rack manufacturers still offer racks that accomodate the Sterilite 1756 tubs (32 quart) and 1754 tubs (15 quart). Unfortunately however, both of these models of tubs have been discountinued by Sterilite and their latest models may not fit into the rack.

You will either have to supply your own tubs, build a custom rack, or purchase both a hatchling AND and Adult colubrid rack.