This secondary computer battery is used to double up your laptop's battery capacity. On select models of ThinkPad laptops, you will find a slot opening near the CD bay. This bay slot is dedicated for a second battery & is a great feature not found on many laptops these days.
IBM ThinkPad Ultrabay 43 Laptop Battery is compatible with ThinkPad T400 Series, T500 Series, R400 Series, T410s Series, R500 Series, W500 series, T60 Series, Z60 Series, select R60 Series notebooks and is compatible with the ThinkPad X6 UltraBases.
This additional battery will provide approximately 1-2 hours of additional run time on top of your main battery pack. This brand new battery features lithium-ion cells. Li-ion battery technology provides longer run times with less weight. In
addition, Li-ion batteries are not subject to the memory effect common with older battery technology. This laptop battery replacement is 100%
compatible with the original battery specifications and is individually tested and backed by a 1 year warranty.