they won’t. it uses the Peltier effect. It has no heating element and the temperature change is slight. These things do work, they take advantage of the bundles of thermoreceptors in your neck (or wrist, as in the case of Embr Wave), concentrating a slight increase or decrease of temp to trick your brain into thinking it’s a lot cooler or warmer. It’s like putting a wet washcloth on the back of your neck but without the sloppy wetness.
