Your 12-24 recovery seed phrase most likely comes from the Bitcoin Improvement Proposal: 39 (BIP 39). BIP 39 is the use of a mnemonic phrase -- a group of easy to remember words -- to serve as your back up recovery in the event your wallet becomes compromised. These words are pulled from a specific list of 2048 words. In this list, the first 4 letters are unique to each word.
Blockplate 12 and 24 is the upgraded version of the original Blockplate. It features a higher quality engraving allow you to be able to easily see and feel the depth of it. It is deeper, darker, and larger. This allows Blockplates to endure even tougher physical, heat abuse, and abrasion.