Want to reuse your smaller sized essential oil bottles? These sets include both a drop by drop applicator and a black plastic cap that are compatible with the standard 15 mL and 30 mL essential oil bottles that our prized oils are packaged in. Available individually, or in cases of 12 or 24. Please note that these reducer caps are not compatible with our other amber glass bottles in the 1/2 oz. and 1 oz. sizes, or the larger sized essential oil bottles.