The Celestron Elements Thermo Charge 6 is a rugged, aluminium, 2-in-1 tool designed for the outdoors featuring a hand warmer & portable power bank. Water-resistant, dust-proof & crushproof, the 6000m Ah rechargeable lithium battery charges two USB (Universal Serial Bus) devices (such as a smartphone & MP3 player) at the same time, & provides up to 8 hours of scent-free heat when being used as a hand warmer.