Elements by Celestron is a line of rechargeable electronic tools designed for the avid outdoorsman. They are water resistant, dust proof, crush proof and drop tested to withstand the abuses of the wild.The Celestron Elements ThermoCharge 10 is a rugged, ergonomic, 2-in-1 tool featuring a Hand Warmer and portable Power Bank. The power curve design allows for comfortable use in both your hands and a pocket, while also maximizing the contact points for heat transfer.The hand warmer is good for a full day of heat- up to 12 hours, at temperatures up to 114