8% of all stains. These sandals fit great and seem to be very comfortable. Basically, youre hired to tutor this schoolgirl and get her through her exam (coming in a week) as best you can. The wheel itself rotates on a simple steel shaft. While I do have Google Assist voice activated on my phone, the "assist" button (as I call it) activates it automatically, which is good if youre an area where voice commands are hard to hear. The memory foam squished down on first day so not much cushioning. When it came, I got it and was soooo excited to put it on and knock everyone dead. especially the low end. After wearing these for about one month - really hoping they would work out for daily fitness walks - am having to give up on this. I received a 1-ear headset, not what the picture and description said I would receive.