I won?t make the call here for you. you?re just supposed to tie it around your waist and hope for the best. S size 11. These went in to the wash immediately and did not stretch. The only gripe I have is that the headset isnt that flexible. everything was still firmly attached and it hadnt moved one bit even when we got to our destination (3 hour drive - all highway). She wore them to a wedding and danced a lot and said they felt good. The back holds them on nicely. They do essentially the same thing but for 30-40 dollars less. The Bluetooth feature is easy to use, and I use this to wirelessly stream music from my laptop or phone.