Nikon EN-EL 4a Compact Lithium-ion power supply for Nikon D2 series D-SLR cameras. Up to 3800 images can be shot on one charge. The EN-EL4a is free from "memory effect", so it can be recharged at any time or any level. A microchip built into the battery measures discharge capacity and compares it to the full (maximum) capacity recorded when the battery was last calibrated. To charge the EN-EL4a use the MH-21.
Nikon EN-EL4a Battery. Original Li-ion rechargeable battery. from Nikon. Will Fit D2H. D2HS. D2X. D2XS. D3. D3S . D3X. D300 and D300S