I wish everyone used this kind of dropper! As silly as it may sound, I think it is a sin to put a restrictor top in a glass bottle. By the time you get any amount of oil out it's ran down your hand an onto the sink. I love these droppers because when you use them they fill the tube with oil. Thus I control the amount of oil that I use. And on most glass bottles once I remove the restrictor the dropper makes a perfect replacement lid.