The BTI Battery is a compatible OEM replacement for the PA5157U - 1BRS P000577250, designed specifically for Toshiba Satellite notebooks including the E45T and E55 series. With a capacity of 4160 mAh and a voltage of 11.4V, this lithium - ion battery ensures reliable power for your device. It features a proprietary battery size for easy installation and is rechargeable, providing longer usage on a single charge. Ideal for users seeking dependable performance and convenience, this battery is an essential accessory for maintaining your notebook's functionality.