Power your devices with this high-performance 4000mAh rechargeable lithium-ion battery pack, designed for a wide variety of applications. With a voltage of 3.7V and a capacity of 14.28Wh, this battery provides long-lasting power for DIY electronics, toys, lighting, Bluetooth speakers, and even medical equipment. Its low internal resistance and PH2.0mm plug make it the perfect choice for efficient and reliable energy storage.