Use this to calibrate your Brix refractometer, Salinity refractometer, Beer refractometer, Honey refractometer, Clinical refractometer, Coolant refractometer, Alcohol refractometer, battery refractometer, or antifreeze refractometer. It works on all types of refractometers. Very simple to use! Open the daylight plate, and place 2-3 drops of this calibration fluid on the main prism. Close the plate, looking into the eyepiece and turn the calibration screw until the boundary between the upper blue field and the lower white field meet exactly on the ZERO scale. It's done! The whole calibration will only take 30 seconds. The Vial contains 2ml, it is enough for at least 30 calibrations. Satisfaction guaranteed or your full money back! Additional Details ------------------------------ Package quantity: 1