This flask is quite ordinary looking, but if magic is detected it will radiate that property. 

The decanter has a stopper, and if this is removed, and the proper words spoken, it will pour forth a stream of fresh or salt water as ordered. 

There are separate command words for the amount as well as the type of water. Water can be made to come forth as follows:

The last shown application causes considerable back pressure, and the holder must be well braced or be knocked over. The force of the geyser will kill small animals and insects (mice, moles, small bats, etc.). The command word must be given to cease.