>I did find, generally, that the Reon Pocket improved matters somewhat, even on its lowest cooling setting. I was definitely still sweating by the time I got home, but the cooling sensation does make a difference while you’re actually out there in the heat.

Sounds like the device is useless then? The impression I got is that it doesn't meaningfully reduce your overall body temperature, but makes one spot cooler which presumably distracts you from the heat. I've heard that peltier coolers aren't very efficient or powerful, so this isn't surprising. Can someone with who studied physics/engineering calculate what the effectiveness of this is, vs a block of ice that's about the same size? Given the high latent heat of water it might be worse than a block of ice..