This specific mattress is NOT self-inflating, as stated in the description. You either have to inflate it with your mouth or purchase (extra) the system with the bag that connects to the inlet and inflate it that way.
Other than that, it is very comfortable and useful (I used it at the beach).
Additionally, its case is very small and only fits after all the air has completely gone out of the mattress (all of it, because if even a little air remains, you can't fold it well enough to fit in the case). I still haven't managed to do this despite all my efforts.
From my packaging, the repair kit was missing, even though it had the note stating that I should leave it for 4 hours without use after repairing it. I assume that's why I paid 75 euros for it.