InfiniBucket
In the game, this modification appears as an "Infinite Water Bucket" - an enhanced version of the regular water bucket. To craft it, you need a standard water-filled bucket and three gold ingots. The main advantage of this item is the ability to use it as a portable endless water source right in your hands.
Using InfiniBucket, you can easily fill any containers: from regular cauldrons to reservoirs and tanks from other modifications. This item is truly indispensable for construction work and automating various processes.

The modification is built using the Forge IFluidHandlerItem interface, which ensures compatibility with most add-ons that properly handle fluid systems. Specifically, it has been successfully tested with reservoirs from ThermalExpansion.
If you encounter compatibility issues between InfiniBucket and any other mod, please report this to the developer with a link to the incompatible content.
Technical Information
The Apache 2.0 license allows free distribution and modification of the project while respecting copyright conditions. The modification can be used in any modpacks without restrictions.