The product line often times referred to as the "Cargille Liquids" or "Cargille Fluids" consist of a number of different product "groups", each one being made up of a different type of microscopy related product, usually used for characterizing the optical properties of a material. The most commonly requested and used of these "groups" are the refractive index fluids and immersion oils.
The "standard group" consists of products used for certification and calibration of equipment and other purposes such as high precision scientific research. Some of the members of this group are also "certified". Other refractive index fluids are available that have been precisely matched to specific applications.