This thing isn't even worth $2. It definitely is not a self inflating pad, like a Therm-A-Rest. You have to blow it up with like 15 breaths. I took it home and blew it up. I then released the pillow valve, and the valve for the main pad. The pad would not self deflate. So, like a typical Therm-A-Rest, I started rolling it up. It's meant to be tolled up. It even has integrated webbing straps to hold it while tolled up. There was a lot of resistance when rolling it up, even though the valve was fully open. It catastrophically popped while trying to roll it up. I've owned a Therm-A-Rest for 28 years. I've used it at least 60 times. It's still as good as the day I bought it. I know how to roll up a self inflating sleeping pad. My guess is that there is too much resistance in the internal baffles, or the valve is defective. Don't waste your money. You'll be disappointed. There's a reason it was on super sale for $15.

I wear a size 11 in closed shoes, and a size 10 in sandals. I bought the size 10 but they are too big. A bit long in the footbed.
Plus, my feet are narrow, and thin top to bottom so the straps are all too long to fit my feet. I really like these, but there isn't a way to make them work. I worry if I buy a size 9, the footbed will be too short. Too bad. They used to advise you buy sandals 1/2 size smaller than normal, and it always works for me.

Bought one from BJ, open today to try it out. It doesn't inflated and no instructions for this. Not recommended