Hello all. Just how durable are these unifs? I had an incident yesterday where all three were placed in a plastic container sized to fit all thee units. As I was removing a tote bag of manuals next to the box of calculators, the box caught onto the bag. Although I removed the tote, the latched up box of calculators fell onto the area rug on top of a wood floor. I guesstimate that the fall was about 30".

As I turned each unit on, each unit looked undamaged and the stack contents were consistent from my previous usage and, as a test, calculating the trademark Mach Number calculation returned exactly the correct answers at each step.

So, even though each unit seems unharmed, to be on the safe side, just how durable is each unit, the 42S, 33s and 35s?

Thanks