It's a tool. It clamps pipes. Similar to flow control pipes, except you can do it on any pipe.

Originally found in https://mods.factorio.com/mod/underground-pipe-pack

If you have both mods, nothing changes.

If you have Advanced Fluid Handling from the above link, don't get this mod unless it's at version 0.16.62 or later. (You don't need this mod anyways as they both do the same thing.)