RSGN-100ATC is an Upgraded Version of RSG-100ATC With an additional Features of BUILT-IN CALIBRATION KNOB, Has much LIGHTER WEIGHT, and LONGERThis hand-held optical refractometer measures the density of sugars in the solution and gives you an instant gravity readings at any point during the boil, or run off from the mash. You do not need to convert the reading from Brix to specific gravity or do an adjustments for temperature.Unlike a hydrometer, it only requires a very small amount sample, about 2-3 drops of sample only. This refractometer is specifically created for brewing of BEER but it can also be great for: Fruits, vegetables & grasses: Monitor and control sugar concentrations in foods, beverages, crops and plants, checking the "ripeness"of fruit in the field and verifying product quality after harvesting and/or controlling concentrations during processing and packaging to ensure product quality Wine or beer: Use Brix readings to get wort sugars and help determine finished alcohol readings (for alcohol reading, best use in conjunction with a hydrometer) Metalworking fluids: Helps in maintenance of CNC coolants and water soluble drawing & stamping compounds and commonly used for controlling the concentration of various industrial fluids like cutting lubricants and flux rinsing compounds The need to consult temperature correction charts is eliminated with the built-in 10-30°C ATC. The unit also comes with a manual calibration knob that is secured with a lock nut and has a brighter display than the more narrow range refractometers. One of the popular instrument with many homebrewers! Measuring Range:Brix Scale:0~ 32% Brix Wort Specific Gravity: 1.000 ~ 1.130 SG Accuracy:±0.2% Brix ±0.001 Wort Specific Gravity