A neodymium power cell was a type of power cell used in Cardassian phase coil inverters. In 2373, Doctor Elias Giger requested a neodymium power cell (among other things) from Jake Sisko and Cadet Nog in exchange for a mint-condition 1951 Willie Mays rookie baseball card. Jake and Nog were able to locate the equipment with Chief O'Brien's help. (DS9: "In the Cards")