Aspirator Reagent bottles, also known as media bottles are containers made of borosilicate glass, plastic, or related substances, and topped by special caps or stoppers. They are intended to contain chemicals in liquid or powder form for laboratories and stored in cabinets or on shelves. Some reagent bottles are tinted amber (actinic), brown or red to protect light-sensitive chemical compounds from visible light, ultraviolet and infrared radiation which may alter them; other bottles are tinted blue (cobalt glass) or uranium green for decorative purposes -mostly vintage apothecary sets, from centuries in which a doctor or apothecary was a prominent figure. The bottles are called "graduated" when they have marks on the sides indicating the approximate (often with a 10% error) amount of liquid at a given level within the container. A reagent bottle is a type of laboratory glassware.