The Nano Saber is a sword added by Industrial Craft 2. It only works when it is activated by right-clicking with it selected in the hotbar. When activated, the Nano Saber will do ten hearts of damage, whereas it will only do one heart of damage when it is not activated.
The Nano Saber can store up to 40,000 EU and can only be charged in Medium or High Voltage Generators, a MV Charging Bench, a HV Charging Bench, an MFE, or an MFSU. The Nano Saber can also be charged with the LapPack equipped in the Torso slot of the inventory.
The Nano Saber is incredibly powerful; the only mobs that can survive an activated Nano Saber are Giants, Zombies, Endermen, Iron Golems, large Magma Cubes, large Slimes, Zombie Pigmen, the Enderdragon, and the Wither. It's also the only sword that is effective against NanoSuit Armor and QuantumSuit Armor, quickly draining their internal EU storage. This is offset, however, by its own energy requirements; the Nano Saber uses 133 EU/t, or about 2,660 EU per second. As a result, the Nano Saber can drain its internal energy storage in about 15 seconds.