Just bought this, their is a slightly cheaper version but its only 1800mAh, I'm no expert but I guess this one lasts longer, also gets good reviews on the site from people who have bought it.
- Top quality product
- Extended your playing time
- Compatible with XBOX 360 wireless controller
- Rechargeable cable: USB to DC 2.35 * 0.7 DC cable with direct plug
- Battery pack: output voltage = DC 2.4V
- Capacity: 3600mAH