There are 2 laptop models from Alienware that share the M15X model name. This battery fits the Alienware Area 51 M15X model. It has a different shape battery cartridge than the M15X models. In order to get the correct battery, you really need to check the battery cartridge in order to avoid a return. (You can find the other Alienware M15X battery Here.)
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 2 year warranty.
You can expect about 3 – 5 hours of run time with this Alienware Area 51 M15X battery when new, depending on your energy use.
This battery replaces the AlienWare Area 51 M15X series laptop batteries.