There doesn't seem to be much difference the way I've had it explained to me, but there must be since it can do so much more. Explained by rubber sheet with weights explanation.
Yes, I remember them. I lived in New Jersey as a young adult and knew a lot of people who would use them, including myself. My dad taught me a trick that I used for a few years. He had studded tires mounted on two extra rims he had. Being we didn't get a lot of snow in NJ he would wait until a snow storm was forecast and had me put them on the day before. The first time we did this it didn't work out too well though. The rims dad had were from previous cars he owned so he figured they would fit the new car he bought earlier that year same maker but they changed the stud pattern. I can't repeat the words he used that day because I would get reported but they weren't nice. After that, the idea worked well. I could change the tires just as quickly as I could put chains on and they could stay on the vehicle until the roads were clear and then change them back. I don't know if you would want to do this if you lived in an area that receives a lot of snow but it worked well when they only had to be changed a couple of times a year. This way you didn't have to worry about the studs wearing down where they were useless or became a hazard.
It is a device that is called a Peltier stack. When you hook it up in one direction, it cools. Reverse the polarity and it heats. They are used in analytical instrumentation to cool detectors down to -20 degrees C. You can get them in a cooler/warming device for around $100 for a 6 quart model. While they won't chill your vodka to -20 C, it will keep your beverages to 2 C. The company that makes a lot of them is Koolatron. Here is a link to them.
