I finally, after years and years, have totally gone away from lab boxes. I still have about 20 of them that I haven't gotten into the newly built rack.
I bought a used mouse rack a year or so ago for $400, holds 35 pans. Then bought another a month later, don't know why it took me so long to do it, I'll never go back!
Finally got off my lazy butt and built one a month ago that holds 40 pans. So far, it's working great, no escapes. But, it wasn't cheap to build. the 3/3 wire is super expensive. But, no more water bottles!