This is a stone bridge I've been using for a little while now. I really enjoy using it, as it fits perfectly into hotel pans (often used by professional chefs). In fact, i use mine with a lexan cambro container like this one: Cambro Clear Food Pan. This bridge is adjustable from 230mm-280mm if used flat and 255mm-305mm if used with the decline attachment (how i use it). You can see me using it in a number of our more recent youtube videos. One of the things that is important to note when using this bridge is that is should be used near the right or left side of your container to minimize wobble. The other thing that is important to note is that while this fits perfectly into hotel pans and hotel pan sized containers, it does not always fit in sinks, nor is it designed to do so (in fact, it was designed to fit with a very specific type of japanese container that is commonly found across japan... it just happens to be about the same size as a hotel pan).
I use this bridge together with my stone holder, though you could easily just put a damp towel on top of it and work that way.