I keep my baby Brazilian Rainbow Boas in these plastic boxes. The boxes are polystyrene plastic from a company called Pioneer Plastics. The boxes are designed to display model cars and come in various sizes. I use the 9.6 inch long boxes for baby BRBs. This size costs around $3.75 each when you buy 24 of them. This size works fine until the snakes are around 26 inches long when I move them into bigger boxes from the same company. Their largest boxes are 16 inches long. The waterbowl is large enough for the snake to crawl into and submerge. The bottom of the cage is lined with a folded paper towel. I use a soldering iron to melt about a dozen small air holes into the boxes. The volume of water in the water bowl and the limited ventilation through the small air holes keeps the humidity high inside the boxes. My snake room is in the 72 to 78 degree range most of the year and I use no special heat for the boxes then. During the winter when I am cooling adult snakes and the room is cooler I use a thermostat and ceramic heat emitter to keep the big cages the boxes are stacked inside in the 70s. The plastic lid on the boxes is a fairly secure friction fit but not secure enough to prevent all escapes so I keep these boxes stacked inside closed 48 inch cages. If I did not have them inside the closed cages I would use tape on both ends of the lids to prevent escapes. The snakes like privacy and they crawl inside the folded paper towel to get it. The high humidity inside the boxes promotes the growth of mold on the paper towels when they get damp which is often so they have to be changed several times a week. Handling several times a week or more is what little BRBs need to initially tame them and to later keep them tame and so they get handled a couple times a week when feeding or changing paper towels and cleaning water dishes. That is 2 inch wide masking tape on the end of each box. I record feedings and shed dates on the masking tape. I have the number for each snake on the outside of the box and also on the inside low on the end of the box for identification when shooting PICs.