The bar in between is kind of flimsy but I found a decent (but low-quality) fix - electrical tape behind the bar will keep it from sliding back and a small piece to hold the bar together. They are flats with no heal. Also, while I was shopping for this product, I REALLY appreciated that all 26 patterns were shown. Now they are not Birkenstocks but I would say that if you want a great pair of shoes, that are close to a Birkenstock and do not want to pay the price of a Birkenstock, these are great. But some of the extreme twists and turns of how this particular family go about things is hugely bizarre. I bought two of them, one for each bathroom. mild annoyance that is irrelevant when you factor in buying the wireless charger at $40 and still being under the asking price of the speaker itself when new. He said these fit like a glove and are very comfortable (size 12 3E), which he has never said about any of the shoes he has tried wearing in the last 10 years. The only thing I can see being a problem for some is the knit across the top is a smidge tight but I also have very high insteps & RA in my feet so it could be just me & I know that they will loosen up in short time. These sandals should wear slowly, but only time will tell!