Compatible with Samsung Galaxy S4 (S IV) . Rechargeable 2100mAH (3.7V) lithium-ion battery. Gives your phone the power to keep on fulfilling your communication needs. Perfect as a handy extra or replacement battery. Battery charger easily and conveniently charges a spare battery. Charges from a wall outlet directly. Allows charging via USB port (USB to USB cable not included). Built-in multi-protection circuits. Small and lightweight for easy storage. Foldable blades make it more portable. LED charging indicator.