These warmers are the best. I use them in my socks and mitts and In the thumbs of my mitts. They do a better job that the charcoal based hand and toe warmers. They were a revelation for me. I ply outside almost every day and my hands and feet are not cold anymore. Even if you end up being to warm and get them humid, you just rub them and flunk them up and they are ready to go.
I almost never use charcoal based hand and toe warmers anymore. Only need them now when it goes below -20! My little beaver fur friends do a better job!
I chose the kids size as I have very small hands and feet. But would not hesitate to use the larger ones for bigger hands and feet.
I highly recommend these for their performance.
Further the company is extremely customer focused and it great!