Unfortunately, I have probably caught a "Monday Model". My daughter wanted to sleep on the mattress in the morning was almost all air out. I have written the manufacturer of the answers that lie at different temperatures and would give use after a few days. So we tried it at least another week. Surely we have the valve closed. Nevertheless, the air is out. Too bad I have no desire to argue with the manufacturer. Anyway, I can only advise against the purchase.