The hand warmer is made of aluminum alloy, and it is safe and non-toxic. It can be used as hand warmer and power bank for your phone. It can be used repeatedly and durable for long time use. Features: High quality aluminum alloy material, safe and non-toxic, sturdy and durable. Lightweight and portable, easy to carry and it will not occupy much space. It can be used to warm your hand in winter and can be used as power bank for your phone. Reusable and durable: it can be used repeatedly and durable for long time use; the cobble pattern hand warm looks fashionable and beautiful. It can be charged quickly and keep warm for a long time; and it is safe and blast-proof. Specification: Condition: 100% Brand New Material: Aluminum Alloy+ ABS Color: Silver, Golden, Rose Golden, Blue, Black(Optional) Size: approx. 10.2*5.9*2.4cm/ 4.01* 2.32* 0.94in Voltage: 5V Charging Time: 5 Hours Weight: approx. 153g/ 5.39oz Package List: 1* Hand Warmer 1* USB Cable 1* Dustcover Bag 1* Hanging Rope 1* User Manual Notes: 1. Please allow 0-2cm error due to the manual measurement. Thanks for your understanding. 2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.