The HeatBank™ rechargeable hand warmer and Powerbank keeps you warm from the office to the woods. The convenient power bank feature also recharges your USB compatible device, so you can stay connected while enjoying the outdoors. Dual sided heat up to 113°F/45°C operating temperature with high and low settings for adjustable warmth. Rechargeable 2600 mah Lithium polymer battery that runs for up to 3 hours.UL Certified.