This is a brand new VGP-BPS31 Replacement battery. The superior Sony cells inside the battery cartridge will provide longer run times between charges as well as a longer service life than cheaper batteries. In addition, Li-ion batteries are not subject to the memory effect common with older battery technology. This means you can recharge your laptop any time without diminishing your battery capacity. The battery is individually tested before shipment and backed by 30 day complete satisfaction guarantee and a 1 year warranty.
You can expect about 3 - 4 hours of run time with this computer battery when new, depending on your energy use.
This battery replaces the Sony Original VGP-BPS31 laptop batteries and additional machines which are listed at the extreme bottom of this web page.