The heel backing is flexible. I put it next to my roku remote for size reference. Im not a fan of flip-flops unless Im going to the beach, yet sneakers are a bit too bulky, and I definitely dont want to wear socks, so these shoes seemed like the perfect middle-ground. we had the speakers running from 11am till 1am at almost full volume (plug in) and they did not get hot or got disconnected what so ever. I am trying to declutter the kitchen as much as possible. Very comfortable, but unfortunately the rhinestones are falling off after wearing a few times. I tried calling the manufacturer for warranty service. I particularly like the fact that I could find a really lovely shoe with lots of sparkles that didnt have a heel 4 inches high in which I could not walk. Ill wear them for my dance class. ) After trying out virtually every other brand of womens sport flip flops like Columbia, Keen and multiple others, I couldnt find a pair that offered enough space at the front to protect your toe and space at the sides to protect the foot.