The black bulb polypropylene caps with straight glass droppers are available in a variety of sizes. The easy to use glass droppers make for an excellent choice for dispensing of many liquid products. Please note, the rubber tops aren't recommended for storage of essential oils, which may eat through the black top.
Extra Small 18/400 neck for 1/2 oz. bottles - 66mm length
Small 20/400 neck for 1 oz. bottles - 75 mm length
Small 20/400 neck for 2 oz. bottles - 89 mm length