This is a high-quality, unbranded 21.6V lithium-ion rechargeable battery with a capacity of 3500mAh. It is designed to provide long-lasting power to your devices, making it perfect for use in consumer electronics. The battery is specifically designed for use in the A11 type unit, and it comes with a unit quantity of one. The chemical composition of the battery is lithium, which ensures that it is durable and reliable. It is perfect for use in a variety of applications, including those that require high power. The voltage of the battery is 21.6V, which is suitable for use in a wide range of devices. With this rechargeable battery, you can enjoy the convenience of long-lasting power without the need to constantly replace batteries.