A refractometer is an optical device that, like a hydrometer, measures the specific gravity of your beer or wort. It does so by sampling a small amount of liquid, and looks at it optically. The main advantage over a hydrometer is the small sample size needed – typically only a few drops.
This is an automatic temperature compensating refractometer with both a Brix (0-32%) and Specific Gravity (1.000-1.120) scale. It comes in a zippered storage bag and includes a sampling pipette and recalibration screw driver.
Read more about how to use a refractometer.