The Iron Waterproof Pipe has up to five inputs and one output.
It will send all incoming liquids in one direction. The direction can be changed by right-clicking the pipe with a Wrench in 2.0.x. The output direction can also be changed by redstone current. Every time it either loses or gains redstone power, it will cycle to a different output. However, it will never output to a Wooden Waterproof Pipe. This combination of properties allows for players to accurately control its output direction from afar, via redstone wiring. In addition, this can be used to distribute liquids among multiple pipes by using a redstone clock.