PETZL - ACCU 2 ULTRA Rechargeable Battery for ULTRA RUSH / ULTRA VARIO HIGH CAPACITY: Lithium-Ion technology offers high capacity (2600 mAh) with reduced weight . ADAPTIBLE: Can perform well at low temperatures. ENERGY GUAGE: Energy gauge allows monitoring of battery's charge level. RECHARGE TIME: 3 hours. WORKS WITH YOUR HEADLAMP WALL CHARGER: Charges with the wall charger included with ULTRA VARIO headlamps.