Adding a tip for comfort...
These work great for me.  However, putting my feet into a gooey cold gel is not my favorite experience.  I started putting the unopened package in a bowl of hot water to heat it up a little before I put them on.  Then I  put socks over it and leave it on for a half hour (instead of 10 minutes).  The socks help keep in the heat a bit and it feels more comfortable and I think it moisturizes better too.
Rating: 5 stars