Stay warm longer with an extra battery for all your Heated Core gear. Features: Re-chargeable 7.4V Lithium-ion battery Approximately 6.5 hours of battery performance at Low setting, 3 hours on the medium setting, and 2 hours on High setting - individual performance may vary depending on heat level selection and usage USB output can be used to charge your mobile device Battery only. Extra charger sold separately Note: Heated Core does not guarantee 3rd party Battery and/or Charger for life. Battery and/or Charger guaranteed against defects in performance for 90 days from date of purchase. Battery life will vary by heat level selection and usage.