[5200mAh Hand Warmers ] Reusable 5200mAh hand warmers, constant long-lasting heat for up to 2-4 hours (less in colder temps), not only warm your hands but also can charge your smartphone in an emergency 2-3 charges (according to your phone battery status), easy to put it in your briefcase and carry it in anywhere [Ergonomic Design] Made of high-tech PC and ABS material, smooth and compact as well as anti-skid in one hand [Fast Heating & 2 Levels] Press the switch and instantly release the warmth for you. 2 levels of temperatures 45℃/113°F and 60℃/140°F at your choice [More Security] The hand warmers have passed full inspection before shipping, have no radiation, overheated/ overcharged/ short-circuit protection, more durable, more safe. [Portable] Pebble-shaped hand warmer & power bank 2-in-1; handy carrying anywhere with any pocket or bag while sporting, fishing, hiking, camping, or skiing. a perfect hand warmer solution in cold weather.