Mugen Power Slim Extended-Capacity Battery for Casio GzOne Commando C771 - Will not fit 2nd generation 4G LTE Lithium-ion technology 1800mAh, 3.7V power rating Extended-capacity battery provides additional talk and standby times without adding thickness to your phone Standard-size battery fits in existing battery compartment without the need for a larger battery cover door Keeps your phone powered even with heavy phone and data usage