Maximal Power DB NIK EN-EL18 2600mAh Replacement Battery for Nikon EN-EL18/ENEL18/D4 and DSLR Camera (Grey) Replacement battery for Nikon EN-EL18 / ENEL18 Chemistry: Li-ion, Output Volts: 10.8V, Capacity: 2600mAh Compatible with Nikon D4 DSLR camera No memory effect and can be charged at any time without harm 3 years