Dropper Boston Round Bottles Our dropper bottles protect your diy essential oils, apothecary, tinctures, and extracts (vanilla bean, vitamin e liquid, plant, herb, etc.) preventing light degradation. Container closures such as standard or measurement droppers perfect for your concentrates. Colors of white, amber, cobalt blue, and more, to block harmful UV rays that will damage your product when stashed away - keeping your oils fresher, longer! Dropper Closures The dropper closure has a rubber top which can be squeezed to draw in liquid and expel it in drops. If using droppers to expel medication or for measure sensitive usage, the closure comes in measured options as well as non-measured options. For measured options, product details must specify "graduated" measurement dropper.