GoVets offers Lab Instruments in the Lab Supplies category to help customers complete their projects. Refractometers are instruments used to measure the refractive index of a substance, which is the ratio of the speed of light in a vacuum to the speed of light in the substance. Refractometers are used in laboratories to measure the concentration of solutions, such as sugar, salt, and antifreeze. Shop today to find the right Lab Instruments for your project.