The Cryptosteel Capsule Duo contains two capsules and a double set of steel character tiles that can be used to store your password or seed phrase. A double set of stainless steel capsules increase your security by adding a redundancy option. One Capsule can store a seed phrase or password composed of 24 words abbreviated to the first 4 letters. Fireproof up to 1400C/2500F. Shockproof. Waterproof. Stainless.