10€ for flip-flops/slippers is not a small amount (+3€ for shipping). You are supposed to be looking for something better than what you find for 4-5€ in cheap stores. So you pay double. First of all, they are somewhat non-slip but not enough. The material has a somewhat hard plastic feel, if you step on the rounded back with bare feet it can hurt your foot. However, they are quite silent when walking. But when you are e.g. in the bathroom and there is water on the floor, for some time afterward, when you walk, there is a sound like whistling, as if air is escaping from inside. I had bought "Pa*ex" before, but unfortunately their price in size 45 skyrocketed to 18€ and I got these, but there is no comparison.