I love these roller caps for my oils! They make it so easy to apply full strength oils or a personalized blend right where you want it, with no waiting for drops. I have these on my daily basics like Frankincense, Lavender, Deep Blue, Copaiba, and Serenity. They are also great for turning empty bottles into roller bottles for your own blends, or for making a cut blend with the hot oils that need dilution before application. I won't be buying roller bottles again!