The 4 - Cell 26Whr Li - Ion Laptop Battery is designed specifically for IBM ThinkPad X40 and X41 notebooks. With a capacity of 1800 mAh and a voltage of 14.4 V DC, this rechargeable battery ensures reliable power for your laptop, allowing you to work efficiently without interruptions. Its proprietary battery size guarantees a perfect fit, while the 26 Wh energy capacity provides extended usability. This battery is engineered for optimal performance, making it an essential accessory for your IBM laptop.