Boston Round Plastic Bottles have a rounded shoulder design that has proven over the years to be one of the most reliable for containing almost any liquid or solid. Use Amber Boston Rounds for light-sensitive materials. The pump, when fully depressed, has the ability to be screwed down. They are perfect for DIY lotions, creams, oils, soap, and other cosmetic formulations. With a different top the bottle can also be used for spraying essential oils, cooking oil, massage oils, beauty products, and other liquid compounds or formulas.