Amazon.com : Powerextra LP-E4 Battery Compatible with Canon LP-E4N Battery and Canon 1D C 1D Mark III 1Ds Mark III Ds Mark IV Digital Camera : Electronics
Amazon.com : DSTE® LP-E4 Replacement Li-ion Battery for Canon EOS-1D C EOS-1D Mark III IV EOS-1Ds Mark III IV Digital Camera : Digital Camera Batteries : Electronics