We are so excited to now be offering fragrance oils. Our fragrance oils are concentrated and never diluted. Some are so strong that they may not smell like their description until they are in product. We sell these by ounces, not by ml. Because some fragrances are more dense than others you will find that some bottles are not as full as others. We want consistency for our customers so although we don't like this look, as soap and bath bomb makers ourselves, we want to make sure your 16 oz bottle has 16 oz of fragrance in it. Our fragrances are bottled in PET and HDPE plastic bottles. Both plastics are non leaching and are very difficult to break. These bottles also help to keep cost and shipping down for you.