HIGH-CAPACITY RECHARGEABLE POWER: Lithium-ion cell supplies long-lasting performance for compatible headlamps. Built for reliable output in cold or variable conditions. MICRO-USB RECHARGEABLE DESIGN: Requires BD 1500 Charger sold separately. This product will not work without the charger. If you don't already own a BD 1500 charger then you will need to buy the battery/charger combo first. Eliminates disposable batteries for more sustainable energy use. COMPACT & PACKABLE: Lightweight design stores easily with headlamp gear. Built for reliable performance during long trips and night missions. OPTIMIZED FOR HEADLAMP USE: Designed specifically for BD 1500 compatible models to maximize runtime and brightness output. DEPENDABLE OUTDOOR PERFORMANCE: Provides consistent power output for long days in the mountains or remote terrain.