This refractometer is for measuring the sugar content of beer and includes an automatic temperature compensation of 10 - 30 degree Celsius. This refractometer can replace your hydrometer for easier and more accurate measurements. Simply use the dropper to take a sample of wort and put it on the prism. Then hold the refractometer up to the light and look through the eyepiece. Due to the dual scale there is no need convert to specific gravity as the scale measures both Brix and SG. Comes in a hard carry case with a 1 year warranty by the manufacture Ade Advanced Optics. Please check out other refractometers available from Ade Advanced Optics on amazon. custom ranges available on request.