A graduated pipette commonly used in medical technology with serologic pipettes for volumetric analysis. Typically the pipettes are vertically stored on holder called pipette stands. The most advance pipette stand can directly control electronic pipettes. Pipette robots are capable of manipulating the pipettes as humans would do. Pasteur pipettes are also called teat pipettes, droppers, eye droppers and chemical droppers. ASTM standard E969 defines the standard tolerance for volumetric transfer pipettes. Early products included microscopes, burets, pipettes, litmus, balances, colorimeters, dissecting kits, and anatomical models. Pasteur pipettes can also be used for microscale distillation. Broken pasteur pipettes should be disposed of in an appropriate glassware container. Gerber developed specialized butyrometers (tubes), pipettes, and centrifuges. It acquired Pfeiffer Glass, Inc. in 1966, a manufacturer of high accuracy volumetric pipettes. These pipettes require disposable tips that come in contact with the fluid. Common in medical technology laboratory setups together with other pipettes. These pipettes operate by piston-driven air displacement. The first simple pipettes were made in glass, such as Pasteur pipettes.