They're with the sponges, washbags etc. I found loads of them in stock in my small local Boots today, but there were none in the large town centre one yesterday. When I was paying for it the woman behind the counter said it was brilliant, the best foot file she'd ever tried and that she'd tried all of them.
Just had my first go with it, feet aren't too bad at the moment, but I am determined to not let them deteriorate like I usually do. Has anyone been using lemon juice like they suggest?