I use Sterilite bins or totes, whatever you want to call them. You can buy them from Home Depot, Walmart, Target. I use the big 66qt one for my large boa and I use 32qt ones for both my yearling boa and my BP. I just fill them high enough to just cover the snakes or a little bit higher. Then I put down a sheet of R-Type foam insulation that I cut to fit on the floor and then put the bin of water on top of it so it holds the heat in the bin. Then I put the snake in and let them lounge around for about 30 mins or so. At first they were scared of it but after a couple times, they are used to it and seem to like it now and like I said, will lounge in there and go under water and "swim" and then just loosely coil up and put there head on their body and relax. The bins are actually for when/if my power goes out in the winter and I'm forced to pack everyone up in bins and transport them into my car and run the heater to keep everyone warm until my power comes back on but they double as great "bath tubs" too.