It will redirect you to a link with the stamp details / flavor like in this example.
but I do not understand. the stamps have inside 6.90 $ in eth?
They are loaded with some ETH for tx processing. More specifically 0.001666666666666666.
Check the link I posted earlier as example, you can click around and get e better idea about it, including transaction history, ownership history and smart contract details.
I was able to order a few more today via the site.
Cheers!