Mugen Power Extended Battery w/ Battery Cover for LG Spectrum VS920 Mugen Power Extended Battery w/ Battery Cover for LG Spectrum 4000mAh, 3.7V power rating; Lithium-ion technology Provides more than double the capacity of the standard battery Comes with an extended battery cover door that accommodates the extended battery and features a built-in kickstand Keeps your phone charged and ready to go, even with heavy phone and data usage