I picked up the CryoTherm Palm to use between heavy sets and it does exactly what it promises. Holding it in my palm during rest periods genuinely seems to bring my core temperature down, and I feel less wiped out heading into the next round. It's simple to use, no fuss, and fits easily into a gym bag. I wouldn't call it magic, but for sprints and interval work it helps me keep the intensity up when I'd normally fade. Solid addition for anyone training hard.