What are the largest tubs?

What are the largest tubs available to the public?..

...And, would it be practical to build boxes for them to fit into, with heat inside?

If anyone has experience with making caging for large boas/retics, please let me know.

Thanks,
Brandon

I think the largets tub for racks are the ones that go in the ve-175 racks.
http://animalplastics.com/
under the whats new section.