They stay cool for a long time.
I love these!  I keep them in the freezer and use them on my fingers, which get swollen and painful due to arthritis.  I have also placed them behind my neck and on my forehead and temples, when I have a migraine.  My boyfriend grabs them when he has a toothache or headache.  So, they get a lot of use!  They keep cool much longer than I expected, too.
Rating: 5 stars