The Petzl core battery is rechargeable and fits all Petzl HYBRID headlamps. The battery has an integrated USB port that facilitates charging. The Petzl HYBRID concept makes it possible to use both the Petzl Core battery and 3 AAA / LR03 batteries. This gives the user the flexibility to change power sources when needed. Where the rechargeable Core battery is recommended for frequent and intensive use, non-rechargeable batteries can be used in emergencies.