Dont take the marketing material at face value. Great for around the house and running quick errands. Love ?em. Hemos probado a ir en metro con ellos puestos y no se escucha nada de fuera. When I received them, I thought I would have to return them. It wont work. I bought these slippers for 3 reasons: sweat, noise, longevity. VERY disappointed. So far so good, I put 10 adult xl hoodies, 3 adult wool coats in a large bag. The clamping force helps with the noise-cancelling, but its also very very noticeable, even when I extend these out to their max-level of extension.