SPT SH-113FB Rechargeable Portable Hand Warmer, Lithium Ion Battery Feature: Approximately 7~10 hours of heating time High and Low heat settings Heat temperature range: 100~~113°F Operating temp range: 14~~113°F Charge time: approximately 5 hours Li-batteries are rechargeable up to 500 times Light indicator AC charger or USB power Rated Current: Input voltage: 5V-1A Li-batteries: 3.7V 2600mAh Timer: 10 hours Color: Black Height: 0.8 Width: 2.6 Length: 3.57 Weight: 3.18 oz.