This pack contains 2 wells of different size. The wells produce water every hour, which can be used for production. Currently, it is not possible to draw water by a trailer.
The small well produces 800 liters per hour and the large well produces 2000 liters per hour. It will only produce water if production has been activated beforehand. Since water currently cannot be taken by a trailer, it only makes sense to distribute it automatically to productions (e.g. greenhouses) via the output mode or to sell it directly.
The basic idea is to make life a bit easier on farms with many greenhouses, so you don’t have to spend all your time driving water.