Each Toasty Feet model fits a range of shoe sizes.
If your existing insole can be removed, use it as a pattern to trim your Toasty Feet.
If you can't remove your existing insole simply trim the Toasty Feet Insole using the trim line guides printed on the insole to make them fit your shoe.
Tip: Start by using a trim line size or two larger than your actual shoe size and try it. If it's too big trim to the next smaller size. You can always trim more off but you can't add it back.