Capillary breakup rheometry is an experimental technique used to assess the extensional rheological response of low viscous fluids. Unlike most shear and extensional rheometers, this technique does not involve active stretch or measurement of stress or strain but exploits only surface tension to create a uniaxial . Hence, although it is common practice to use the name rheometer, capillary breakup techniques should be better addressed to as indexers. At present, the unique commercially available device based on capillary breakup technique is the .