After a late September section hike in GA. where my buddy had some difficulty with the unseasonably warm temperatures, my wife asked me if I carry an instant ice pack as part of my first aid kit. My search turned up these small Icy Hot Instant Cold Packs which are meant to be inserted in knee braces. They weigh just 3.2 oz and could come in handy in the absence of a cold stream. However, searching the First Aid Kit thread for "ice packs" turned up nothing. I added one to my kit anyway. Granted it's all personal preference, but does anyone carry anything similiar or do most consider it unnecessary?