This is a Genuine Sony brand battery  with extended run capacity. This long run battery will run at least 50% longer than the 6 cell battery that ships standard with your laptop. The added run time is achieved with an additional 3 cells inside the cartridge. This longer running battery will extend to the bottom of your laptop about 1 inch. Users of this battery pack experience an additional 1-2 hours of run time over the standard battery. Estimated run time with this battery is 3-5 hours. Longer run times can be achieved by minimizing the power use, especially the screen brightness. 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.

The additional cells contained in this battery will protrude to the bottom of your laptop about 1 inch and add about 5 ounces of additional weight. The added height will also provide more space for air circulation and cooling underneath your laptop. The battery is designed to fit perfectly into your laptop and includes rubber feet which will rest on your table surface.

A word about alternate brands of batteries for Sony laptops: Sony laptops are equipped with proprietary software which interfaces with the computer chip in your Sony battery pack. Other battery brands will require a software update to change your computer's BIOS in order to recognize their battery. This can be a potentially risky operation with a worst case scenario of completely disabling your laptop. In particular, laptops which use the Windows 7 operating system have a very low success rate with BIOS updates. Sony genuine brand batteries are "plug & play" ready as soon as you snap them in. This battery will deliver 77% more run time than original 6 cell version that came with your laptop. If you prefer the 6 cell battery, click here for the Genuine Sony brand 6 cell battery (SON-VGP-BPS21A).

This battery replaces Sony laptop models that begin with these series numbers: VGN-FW, VGN-NW, VGN-NS, VGN-CW, VGN-AW, VGN-BZ, VGN-SR, VPCB1, VPCCW1, VPCF1, VPCS1, VPCY1, VPC-CW, VPC-F, VPC-S, VPC-Y