Bottles are most often used for chemicals and other liquids. Bottles typically have a neck that’s smaller in diameter than the rest of the container. Bottles are available in different shapes, like Boston rounds, packers, squares, media, and more. Bottles are the additional products of glass (clear or amber) and natural or colored plastics. Choose clear glass or natural plastics for optimum visibility and amber-tinted glass and plastic for light-sensitive materials. Most bottles are sold with attached or separate closures.