BP2V/BP4V HB is the upgraded version for Sony Vaio that can extend the laptop battery life evidently. Carrying with this 12-cell lithium-ion replacement battery, users don? need to worry if your laptop computer is out of power or last for only a short period. Output power of 11.1V and 8800mAh is able to supply enough standby time and lifespan to Vaio PCG-591L, PCG-V505, PCG-Z1, PCG-VX, VGN-B, V505, VGN-B and so on. Whether or not you have enjoy the additional functions of high-capacity Sony Vaio BP2V/BP4V HB laptop batteries, this 12-cell version is bound to satisfy you in all aspects or surpass your expectation.