Extended Battery for MSI Wind U100, U100 series 4400mAh (6-cell) rechargeable battery guarantees long running times and absolute freedom. Allows the user to become even more mobile! One-Year manufacturer's warranty. Among the most powerful batteries available for the MSI U100/Medion Akoya Mini series devices. Latest Lithium Ion battery technology gives the best performance possible compared to other battery technologies. Amperage: 4400mAh; Voltage: 11.1v