They seem nice and roomy for a box and the same bottom dimensions as a 50 gallon breeder tank(inside 36"x18" with less angled sides than cb70 tub)cages are certainly better for many reasons but this seeems like a nice size compromise option.
Took an adult Amel. corn out of a Neo 4' slant cage and the corn has almost the same bottom space in the tub. This corn (my daughters pet) is not much of a climber and seems to be reacting fine to the tub. initial cruising to check out new digs and now very laid back relaxed body movements ( sometimes calmly stretched out or loosely coiled, not cowering tightly coiled in a corner and seemingly stressed at any movementd)
This may be a winner tub. while limmited in height for climbing species, In the distant past I would have felt comfortable keeping a small colubrid like this corn in a 50 gallon in the day. 

