Water Cell is an IndustrialCraft 2 fluid container that holds one unit of water inside a reusable-looking tin capsule. Players make a Water Cell by holding an Empty Cell and right-clicking a water source block, exactly like filling a bucket, or by combining an Empty Cell with a Water Bucket in the crafting grid. Empty Cells themselves come from tin — in IC2 Classic 4 tin ingots craft 16 cells, while IC2 Experimental forms them from tin plates in a Metal Former. The most important role of the Water Cell is feeding IndustrialCraft 2's cooling chain: water is enriched with Lapis Lazuli Dust in a Canning Machine to create Coolant, which fills the Coolant Cells that absorb heat inside a Nuclear Reactor. Because IC2 nuclear power is heat-driven, a steady supply of Water Cells underpins safe reactor operation and the crafting of Overclocker Upgrades. The Water Cell is a single-use capsule, so it is consumed in most recipes rather than returned. Keep a stack on hand when scaling up an IC2 reactor or processing plant, since water is the cheapest input in the whole nuclear pipeline.