A small round cantine, that is strapped around its wearer with a leather strip. It has the ability to never run dry. It will be able to contain any type of liquid such as acid or lava. It will also never run out.
An alchemist enchanted his equipment to produce even more powerful alchemical compounds, potions and the like. Unfortunately, it is not well-known that he had different sets of equipment for different processes: If the wrong set of gear is used, the result will invariably fail to function. It's not a cursed item, just something that's hard to figure out.