42T5227 - Lenovo 4-Cell Battery for ThinkPad T61 R61 R61I R400

Technical Specs:
- Battery type: Li-ion
- Number of cells: 4
- Voltage: 14.4V
- Capacity: 2600mAh
- Power output: 38Wh
- Dimensions: 206mm x 51mm x 20mm
- Weight: 0.3kg

Helpful notes:
- This battery is compatible with several ThinkPad models, including T61, R61, R61I, and R400.
- It is a 4-cell battery, which means it is smaller and lighter than some other options.
- The Li-ion technology provides a longer lifespan and better performance than older battery types.