So good. These hand warmers heat up quickly and work really well. They seem very well made and are robust yet stylish. They also come with lanyards & cables, so there's everything you need. Once charged, they last a long time. The heat is good and there are 3 levels. The handwarmers can be used seperately or they can form one big one by pressing the two together (they have magnets that make them stick). They can also be used as power banks. Best hand warmers I've used.