Bip39 hardware https://telegra.ph/Producing-Custom-Bitcoin-Addresses-A-Take-A-Look-At-BIP39-Strategies-06-28 Abra - A cell wallet that supports BIP39 seed phrases, giving both of those wallet and exchange features for cryptocurrencies. For words that have only three letters, there is not any 4th letter. As an example While using the word “insert”, there won't be any more letters https://thebookmarknight.com/story20589606/bip39-balance-checker-5-essential-elements-for-bip39-word-list-pdf-https-www-youtube-com-channel-ucupxfytj0fb78sq55hu6ocw