Isn't stamping washers also storing your seed on tiny pieces of metal? The only other real alternative is one of those steel plate things. It's got a matrix of letters and numbers, and you use a center-punch to mark each of your seed letters in the space provided. They're popular, and several companies make variations of it, but I don't really like them because of the size. The capsule is ideal for my desires. It's secure, and the form-factor allows it to be stored very easily, or even hung around your neck if you want. Looking at the temperatures and conditions it's rated to withstand, I'm very comfortable storing my seed on it.