I have bought some of these shoes before, years ago in a Galveston shop. And I have worn them a lot. They are some kind of rubber or plastic,  so they can get wet. They are comfortable and durable. The size runs normal. I wear 9 in shoes and in these too.
I'm getting more so I will have them  in case my old ones wear out. And I discovered more colors.
The prices are low enough to get several colors.