Refractometers are used to measure and index refraction, often calculated using Snell's law. Handheld, analog, digital and brix refractometers are used for a variety of applications to measure salinity and glycol, from beer and winemaking to beekeeping. Similar to refractometers, polarimeters are used to measure the angle of rotation caused by passing polarized light through an optically active substance. Refractometers are also used in pharmaceutical, medicinal and laboratory settings. For more types of test and measurement products, see our manometers, force gauges, and chemical test strips.