Bip39. Remember, there's no such thing as being a “Improper” passphrase. Each distinctive passphrase you enter is usually a entirely new wallet. Be cautious when recovering your seed having a passphrase. What constitutes a "very good wallet" is one that has distinct, easy to obtain documentation on supported BIP benchmarks, https://ragingbookmarks.com/story19539727/bip-39-https-linktr-ee-bip39-how-much-you-need-to-expect-you-ll-pay-for-a-good-bip39-generator