'Stamps' in the Bible

And I saw in the right hand of him who was seated on the high seat, a book with writing inside it and on the back, shut with seven stamps of wax.

And I saw a strong angel saying in a loud voice, Who is able to make the book open, and to undo its stamps?

And one of the rulers said to me, Do not be sad: see, the Lion of the tribe of Judah, the Root of David, has overcome, and has power to undo the book and its seven stamps.

And I saw when the Lamb undid one of the stamps, and the voice of one of the four beasts came to my ears, saying as with a voice of thunder, Come and see.