Absolute Zero™ Discharge Tray A good discharge tray is essential for maximum performance of any battery pack. Even though Ni-MH packs have no "memory" they perform better with a complete discharge after ever run on the track. The Absolute Zero Discharger was made especially for the needs of Ni-MH cells. Green light turns off when pack reaches 5.4 volts, Red light turns off when pack reaches 3 volts, Cell monitoring lights dim when cell reaches .85 volts. You can safely leave the pack in until all the cell monitoring lights go out. Remove batteries and your ready to charge again. Discharges 1-6 cells in any combination!