The DENAQ 3 - Cell 29Whr Li - Ion Laptop Battery is designed specifically for IBM ThinkPad models R50, R50p, R51, R51e, T40, T40p, T41, T41p, T42, T42p, T43, and T43p. With a capacity of 2600 mAh and delivering 10.8 V DC, this rechargeable battery ensures your notebook remains powered for extended periods. Its lithium - ion chemistry offers enhanced usability and longevity, making it a perfect replacement for aging batteries. The proprietary battery size guarantees optimal performance, while the 29 Wh energy capacity provides dependable usage for your computing needs. Ideal for professionals and students alike, this battery is a cost - effective solution to keep your laptop running smoothly.