Replace old and worn out batteries in your laptops with the BTI Notebook Battery. This Li-polymer battery makes for an ideal back up for your original batteries while travelling. With a power of 3290 mAh, it ensures hours of uninterrupted use on a single charge. It is designed for use with the Lenovo ThinkPad X1 Carbon 4th Gen Notebook. Made from quality components, this BTI notebook battery offers durability and longevity.