I have a stroud that works wonders. It was like 60-80 bucks.
I freeze it before i go to the track and it last a couple hours.
Then i put in the bottom of the ice chest to soak up some water and good for about an hour. Its wet but it works great .
I have one and it works great. I don't really care for the bulkiness of the ice packs so after freezing them I actually let them sit out for awhile until they're almost slushy. Less bulk under the fire suit and still keeps me cool.
I use one, they are great when it is 100*F and the staging lanes are slow, I can sit in comfort. I have 2 complete sets of ice pacs, when I am done my run I just throw the whole vest i the RV freezer and it works great.
I use one thats similiar to that (i have had for too long to remember where I got it, maybe "goodvibrationmotorsports") I love it, has two sets of ice packs. Exchange them out after a run or two and its great to be in the lanes w/ a 20 layer suit zipped and people think your nuts until the realize youre not sweating. Money well spent!