Billfodl can be purchased at billfodl.com. It makes the following durability claims:
Very easy to set up, just requires a flathead screwdriver to unlock and start sliding in the laser engraved stainless steel letters. It took me a few minutes to figure out how to actually unlock the gate in order to slide in the letters since there were no instructions provided.
Heat Stress Test
Unfortunately the heat managed to warp the tray enough to loosen the letters and a bunch of them fell out. While the device itself remained intact, I have to consider this a catastrophic failure.
Corrosion Stress Test
Was unaffected by the acid; looked the same as after the heat test.
Crush Stress Test
Fairly resistant to crushing in terms of the overall device. However, it’s not nearly as robust when it comes to handling deformation of the device without suffering from data loss. The rail-based design of these devices results in them suffering from data loss more easily, because even slight deformation results in letters falling out of their slots. By the time I pried them back open, pretty much all of the letters had fallen out.