File:Nikon EN-EL4 retail box 20061230.jpg - Wikipedia
Amazon.com: Synergy Digital Camera Battery, Compatible with Nikon D2X Digital Camera, (li-ion, 11.1V, 1800 mAh) Ultra High Capacity, Replacement for Nikon EN-EL4 Battery : Electronics
Kastar 4-Pack EN-EL4a Battery 11.1V 3200mAh Replacement for Nikon EN-EL4, EN-EL4a, EN-EL4e Battery, MH-21, MH-22 Charger, Nikon Camera D2, Nikon Camera D2H, Nikon Camera D2Hs, Nikon Camera D2X - Walmart.com
Nikon EN-EL4 Li-Ion Battery (D2H,D2X,D2XS,D3,D3X) Requires BL-1,BL-4 Cover at KEH Camera