The BTI notebook battery is designed to deliver reliable power for extended periods, ensuring your device operates smoothly. With a voltage output of 15.44 V and a capacity of 5570 mAh, this 4-cell lithium-ion battery provides the necessary energy to keep your laptop running efficiently. Its 86 Wh capacity enables sustained productivity whether for work or entertainment. This replacement battery is compatible with Lenovo L21M4P74 and crafted to meet strict performance standards, offering a dependable alternative for powering your notebook.