Very nice and soft velvet. These are so much nicer than the standard rubber flip-flops you see in most stores. Will be especially loud and frequent once your feet get sweaty if they do. He says very comfortable. One of the last paragraphs, after all the installation steps tells you that one is longer than the other and it goes on the front. I have an Samsung S8+, with a thin case added, which really stretches this thing to its limit. Kind of a crowning justification that my efforts in sound quality have been worth it. Allright! (And a patio screen) So, I wear these a lot. Fabulous product.