SeedSteel is no longer available; it used to be sold at seedsteel.com. It looks pretty rudimentary — two thin steel plates sandwiched between two really thick steel plates. Came with a center punch to write words as dots, which was odd.
Not much to say here — it’s two sheets of metal sandwiched between two thicker sheets of metal. No problems with etching or stamping.
Heat Stress Test
Lots of discoloration on the interior metal sheets, but still quite readable.
Corrosion Stress Test
No data loss of any of the writing types.
Crush Stress Test
No data loss.