Some like it hot!
There are red lights around the entire inside of the collar and an infrared heat coil over the spine in the back segment of the collar. It's easy to open and slide around your neck (which I tend to do from the front or side, then rotate the collar into place) and then short-press the power button on the front outside of the collar to start it. You can long-press to stop it at any time or short-press to cycle through 3 heats levels. The red lights appear to have only one intensity (yes! I wouldn't want them to dim). Even the lowest heat (#1) is pretty toasty, and I'm a gal who normally runs infrared as hot as it goes. After about a minute, it's too hot to press directly against my neck, but the collar design allows me to shift it slightly back and it'll stay that way. Overall, I'm pleased. Most red light devices don't allow good coverage of the neck, but this one does.
Rating: 4 stars