About Boston Round Bottles with Glass Eye Droppers. Boston Round Bottles (also known as Winchester Bottles), are made of premium quality amber glass, durable and reusable, can hold almost any liquid, ideal for the cosmetic, medical, and aromatherapy industries. Dropper assemblies are composed of three parts: the cap, the silicone top and the glass pipette (tube), ensuring you suck up and dispense liquids easily. Great for essential oil, perfume oil, cosmetic products, homemade tinctures, food coloring, health care, e-liquids, chemistry lab chemicals, or any liquid requiring protection from light.