I use a bit of castor oil in nearly all of my soap recipes, so I bought a gallon jug (7-lb size). However, getting "just enough" castor oil to pour out was a chore. Not any more! I use this pump to slowly add the oil to my measuring bowl on the scale, and I haven't had an overpour since I got it. I also use these pumps on other liquid oils (rice bran oil, sweet almond oil, etc.) that are used in smaller quantities; however, olive oil is better to pour directly from the jug!