The Dell 0K3N6W is a 3-cell lithium-ion spare battery for Dell notebooks, intended to replace a notebook battery.
It provides 40 Wh of energy capacity, with listed electrical specifications of 3378 mAh and 11.25 V. These values identify this particular 3-cell variant and help distinguish it from batteries with different capacities or cell counts.
Use it as a spare in a compatible Dell notebook to power the computer when it is away from its power adapter.