Pump (gallon jugs)

One of these is a necessary tool for certain products. For others - such as bubble bath, facial toners, etc. - it causes too much agitation, allowing a bubbly build-up (if you will!) which in turns leads to a delay in filling.
I personally think they are too expensive, but as I said, a very handy tool and a must-have. I do like that it will fit two sizes of bottles.