These stainless steel plates are etched with a grid on both sides. The grid contains the alphabet along the Y-axis and 48-columns along the X-axis. The 48-columns are split into 12 groups of 4-columns. Each of the 12-groups has enough room for 4-letters. Only the first 4-letters of each BIP39 seed word is required in order to restore the wallet as no two words on the BIP39 word list share the same sequence of the first 4-letters.
Use a marker to indicate the first 4-letters of the first 12-words on one side of the plate and then flip the plate over and repeat the process for the 13th through 24th words. Double check your work then use a spring-loaded punch to stamp the plate on each mark.
Now you have a robust stainless steel backup that can withstand fire and flood. This backup plate is easy to conceal measuring in at 127mm X 76mm x 1.5mm so that it can be hidden in a variety of places and environments.