There are many metal backup products. This guide, part of our metal seed phrase backups section, shows you how to judge them.
What to look for
| Criterion | What is good | What to avoid |
|---|---|---|
| Material | 304 or 316 stainless steel, or titanium | Aluminum, brass, plated metals |
| Word storage | Holds 24 words, at four letters each or more | Too little room |
| Retention | Letters stay in place after heat and impact | Loose parts that can scatter |
| Readability | Stays readable after damage | Shallow marks |
| Ease of setup | Mistakes are unlikely | Fiddly tiles that take hours |
| Tamper evidence | You can see if it was opened | No seal |
| Simplicity | No app and no electronics | Anything that goes online |
The main types
| Type | Examples | Good | Trade-off |
|---|---|---|---|
| Stamped or punched plate | Blockplate, SeedPlate, DIY plates | Solid, with no loose parts | Needs tools and care |
| Letter tiles | Billfodl, Cryptosteel Cassette | No tools needed | Parts can shift in extreme conditions |
| Capsule | Cryptosteel Capsule | Compact | Check the seal and the capacity |
| DIY washers | Stamped stainless washers on a bolt | Cheap and private | Your own quality control |
Examples are not rankings, and designs change. Our guide to tiles, plates and capsules goes further.
What public stress tests show
Jameson Lopp has run a long series of public tests, in which he heats, crushes and corrodes metal backups. His reports give useful evidence, and you can read them yourself in round II and round IV. Solid designs in stainless steel have generally held up well, while many tile designs are more vulnerable to crushing and to tiles falling out. Check his latest results before you buy.
Before you buy
- Decide how you will store it. See where to store a seed phrase.
- Check that it fits 24 words if your wallet uses them.
- Read how the maker handles orders and data. Anonymous ordering is worth considering.
- Try it first with made-up words.
A cheap alternative
You do not need to buy a branded product. A plain stainless steel plate and a letter punch set can work very well. See how to stamp a seed phrase on steel.
After you buy
Verify every word, and test your backup. See why four letters are enough and how to test your backup. Never share your words with a backup company.