Quality materials: the metal crypto wallets are made of 304 stainless steel with a melting point of over 2500 Fahrenheit degree, fireproof, waterproof, shockproof, hacker-proof and not easy to break, can be preserved for a long time | What you get: the crypto wallet set includes 4 plates steel wallets, along with 4 matching lock screws kits for easily assembling, enough to meet your back-up preservation needs | Passphrase field design: each cryptocurrency seed storage wallet is designed with several passphrase fields, you can engrave on 12 or 24-word seeds in any languages to build your own seed storage system, and tighten it with screws for privacy | Proper size: the crypto steel wallet is compatible with BIP39 wallets, works well with most hardware wallets and supports up to 24 mnemonics seed phrase; Suitable size, so that these cryptocurrency steel wallets can be fit in most password cases | Wide applications: you can lock up the crypto hard wallet to prevent your privacy or important information from leakage; The hole on this steel wallet is 6 mm/ 0.24 inch in diameter, and you can use strap or lanyard to attach it to keychain or concealed of backpack to avoid losing