1Product Material: Hand warmer is made of zinc alloy, surface adopts electroplating and polishing treatment, durable to use. 2Heat Dissipation Holes: There are 21 heat dissipation holes on the front and the back and 5 holes on the top, star shaped, radiating constant temperature heat. 3Hand Warmer Size: Hand warmer size is 90x57x20mm / 3.5x2.2x0.8in, suitable size and convenient to carry around, providing users a good using experience. 4Lightweight and Small: The lightweight and small size allow you to put it in your pocket or carrying bag, easy to carry and store. Simple and convenient to use. 5Wide Range of Use: Portable hand warmer is suitable for outdoor, office, anytime, anywhere, easy to carry, suitable for the elderly, pregnant women, and children.