Features: These batteries are suitable for flashlights and other electronic products. The 3.7V 5500mAh 26650 rechargeable Li-ion battery is equipped with a protection circuit board(PCB) on the positive pole. The PCB can protect batteries from overcharge, over-discharging, overload and short circuit, which can make batteries safer and longer lifespan. The battery is environment friendly and perfect for super bright flash and other devices. Size: 68.5mm26mm(Height * Diameter).