It is always good to have extra batteries when using a vaporizer, so you always have fully charged batteries ready to use when your battery runs out. Sometimes the batteries die and won't charge again. The Haze Rechargeable Battery pack comes with 2 Haze Lithium-ion rechargeable batteries. They're 2600mAH Li-Ion 18650 3.7 V which is recommended for use for the haze vaporizer and charges best with the Haze Wall charger. Purchasing the Haze Rechargeable Battery pack does not come with a wall charger.